

ThreeGorges Dam Fine Sediment Pollutant Transport: Turbulence SPH Model Simulation of MultiFluid Flows


Pages :
110


Authors :
J. H. Pu,
Y. Huang,
S. Shao,
K. Hussain,
The Three Gorges Dam (TGD) constructed at the Yangtze River, China represents a revolutionary project to
battle against the magescale flooding problems while improving the local economy at the same time.
However, the largescale finesize sediment and pollutant material transport caused by the TGD operation are
found to be inevitable and longlasting. In this paper, a multifluid Incompressible Smoothed Particle
Hydrodynamics (ISPH) model is used to simulate the multifluid flows similar to the fine sediment materials
transport (in muddy flows) and water flow mixing process. The SPH method is a meshfree particle modeling
approach that can treat the free surfaces and multiinterfaces in a straightforward manner. The proposed
model is based on the universal multifluid flow equations and a unified pressure equation is used to account
for the interaction arising from the different fluid components. A SubParticleScale (SPS) turbulence model
is included to address the turbulence effect generated during the flow process. The proposed model is used to
investigate two cases of multifluid flows generated from the polluted flow intrusions into another fluid. The
computations are found in good agreement with the practical situations. Sensitivity studies have also been
carried out to evaluate the particle spatial resolution and turbulence modeling on the flow simulations. The
proposed ISPH model could provide a promising tool to study the practical multifluid flows in the TGD
operation environment.





Magnetohydrodynamic Boundary Layer Slip Flow and Heat Transfer of Power Law Fluid over a Flat Plate


Pages :
1117


Authors :
J. Hirschhorn,
M. Madsen,
A. Mastroberardino,
J. I. Siddique,
In this paper, we consider the magnetohydrodynamic (MHD) boundary layer flow and heat transfer
of power law fluid over a flat plate with slip boundary conditions. We use a similarity transformation
to convert the governing nonlinear partial differential equations into a system of ordinary differential equations and solve the resulting system numerically using MATLAB’s boundary value solver,
bvp4c, and the shooting method. We present velocity and temperature profiles within the boundary layer and demonstrate the effect of changing the magnetic parameter, Prandtl number, and slip
parameters.





Investigation and Comparison Effects of Fluid Injection Type in Thrust Vector Control


Pages :
1926


Authors :
M. R. Heidari,
A. R. Pouramir,
In this research, the effects of some liquid side injection from nozzle wall into exhaust gas of combustion
chamber are studied. The side injection against main flow is as elliptical solid thing that change the
symmetric of flow field on nozzle wall and causes some different pressure distribution on wall, and finally
causes thrust vector deviation. Flows interaction causes some physical phenomena as bow shock wave in
front of injection region. This paper explain the effects of this wave and variation velocity & pressure
distribution at different cross sections of flow field and comparison results of air and other liquid fluid in
thrust vector control system. The results are compared with experimental data and have well agreement with
them. The results show that Freon is one of best injection liquid for this type of thrust vector control.
Performance of Injection is optimum in relative position 35 to 40% nozzle divergence length.





WindInduced Ventilation Based on the Separated Flow Region


Pages :
2732


Authors :
M. Rahimi,
M. Javadi Nodeh,
An experimental investigation was conducted to study the potential use of the pressure reduction within the
separated flow region followed by the wake at the leeward direction of a solid surface in natural ventilation of
buildings. Air flow with mean velocity up to 7 m/s was directed onto a solid surface (circular plate and a
semispherical surface) behind which the top end of a vertical vent pipe had been placed. Pressure reduction
at the exit section of the pipe, which was well inside the separated flow region, induced an air flow within the
pipe. This air flow rate from the stagnant surroundings into the wake region was measured under different
geometrical configurations and for various wind velocities. The study revealed that the pressure reduction
within the separated flow region would be applicable for natural ventilation of different spaces at least as an
auxiliary system. The spaces include; sanitary places, crop protection stocks, industrial workshops and other
spaces where no regular ventilation is required.





Film Cooling Effectiveness Enhancement Applying another Jet in the Upstream Neighbor of the Main JetUsing LES Approach


Pages :
3342


Authors :
M. R. Salimi,
M. Ramezanizadeh,
M. TaeibiRahni,
R. FarhadiAzar,
Flow hydrodynamic effects and film cooling effectiveness of placing a coolant port (upstream jet) just
upstream of the main cooling jet were numerically investigated. The upstream jet was added such that the
total cooling cross section (cross sections of the main and upstream jets) remains constant, in comparison to
the case of ordinary cooling jet. The finite volume method and the unsteady SIMPLE algorithm on a multiblock nonuniform staggered grid arrangement were applied. The large eddy simulation (LES) approach with
the one equation subgrid scale model was used. The jet to cross flow velocity ratio (for both of the main and
the upstream jets) is 0.5 and the cross flow Reynolds number (based on the main jet parameters) is equal to
4700. The obtained results showed a significant improvement in the flow control capability and both
centerline and spanwise averaged film cooling effectiveness applying the new cooling configuration. Effects
of the upstream jet dimensions are also studied here. The obtained results showed that the spanwise width of
the upstream jet has more essential influence on the cooling performance than that of its streamwise width.
Moreover, it is demonstrated that the film cooling performance could be enhanced even by applying an
upstream jet which its temperature is as same as the crossflow temperature, i.e. applying a hot upstream jet.
Finally, it is shown that presence of the upstream jet decreases the streamwise component of the velocity
near the wall, which decreases the wall shear stress and the skin friction drag coefficient significantly.





Mixed Convection Flow of Couple Stress Fluid in a Vertical Channel with Radiation and Soret Effects


Pages :
4350


Authors :
K. Kaladhar,
S. S. Motsa,
D. Srinivasacharaya,
The radiation and thermal diffusion effects on mixed convection flow of couple stress fluid through a channel
are investigated. The governing nonlinear partial differential equations are transformed into a system of
ordinary differential equations using similarity transformations. The resulting equations are then solved using
the Spectral Quasilinearization Method (QLM). The results, which are discussed with the aid of the
dimensionless parameters entering the problem, are seen to depend sensitively on the parameters.





Evaluations of Flow and Mixing Efficiency in the Kneading Disks of a Novel TriScrew Extruder


Pages :
5160


Authors :
X. Z. Zhu,
T. S. Wang,
G. Wang,
The forward or backward stagger angles of the kneading disks have great effects on configures of the special
center region along axial length in a novel triscrew extruder. In this paper, the flow and mixing of a nonNewtonian polyethylene in kneading disks of a triscrew extruder were simulated using threedimensional
finite element modeling based on mesh superposition technique. Three types of kneading disks, neutral
stagger, staggered 30° forward and staggered 30° reverse were considered for the triscrew extruder. The
effects of stagger angles of kneading disks on the flow pattern in the triscrew extruder were investigated.
Moreover, at different stagger angles, the dispersive and distributive mixing efficiencies in the kneading disks
of the triscrew extruder and the twinscrew extruder were calculated and compared by means of mean shear
rate, stretching rates, maximal stress magnitudes, mixing index, residence time distribution (RTD) and
logarithm of area stretch. It is found that increasing the stagger angles decreases the axial velocities of
polymer melt in the center region for the triscrew extruder. The staggered 30° reverse is relatively reasonable
for the triscrew extruder and neutral stagger for the twinscrew extruder for the mixing efficiency. In
comparison, the kneading disks in the triscrew extruder have higher distributive and dispersive mixing
efficiencies than those in the twinscrew extruder with the same stagger angles.





Finite Difference Analysis of Thermal Radiation and MHD Effects on Flow past an Oscillating SemiInfinite Vertical Plate with Variable Temperature and Uniform Mass Flux


Pages :
6169


Authors :
R. Muthucumaraswamy,
B. Saravanan,
MHD and thermal radiation effects on unsteady flow past an oscillating semiinfinite vertical plate with
variable surface temperature and uniform mass flux have been studied. The dimensionless governing
equations are solved by an efficient, more accurate, unconditionally stable and fast converging implicit finite
difference scheme. The effect of velocity, concentratiion and temperature profiles for different parameters
like magnetic field , thermal radiation, Schmidt number, thermal Grashof number, mass Grashof number are
studied. It is observed that the velocity decreases with increasing values of the magnetic field parameter or
radiation parameter.





Electrohydrodynamic Dispersion with Interphase Mass Transfer in a Poorly Conducting Couple Stress Fluid Bounded by Porous Layers


Pages :
7181


Authors :
N. Rudraiah,
K. S. Mallika,
N. Sujatha,
Exact analysis of miscible dispersion of solute with interphase mass transfer in a poorly conducting couple
stress fluid flowing through a rectangular channel bounded by porous layers is considered because of its
application in many practical situations. The generalized dispersion model of Sankarasubramanian and Gill is
used, which brings into focus the exchange coefficient, the convective coefficient and the dispersion
coefficient. The exchange coefficient comes into picture due to the interphase mass transfer and independent
of solvent fluid viscosity. It is observed that the convective coefficient increases with an increase in the
porous parameter while it decreases with an increase in the couple stress parameter. The dispersion
coefficient is plotted against wall reaction parameter for different values of porous parameter and couple
stress parameter. It is noted that the dispersion coefficient decreases with an increase in the value of couple
stress parameter but increases with porous parameter.





A Developed Methodology in Design of Highly Loaded Tandem Axial Flow Compressor Stage


Pages :
8394


Authors :
H. Eshraghi,
M. Boroomand,
A. M. Tousi,
This study, primarily reports the development of a 3D design procedure for axial flow tandem compressor
stages and then the method is used to design a highly loaded tandem stage. In order to investigate the effects
of such arrangement, another stage with conventional loading with single blade for both rotor and stator rows
is designed with similar specification. In order to ease the comparison of results, chord lengths and
hub/shroud geometries are selected with the same dimensions. At the next stage a three dimensional
numerical model is developed to predict the characteristic performance of both tandem and conventional
stages. The model is validated with the experimental results of NASA67 stage and the level of the accuracy
of the model is presented. Employing the model to simulate the performance of both stages at design and offdesign operating points show that, tandem stage can provide higher pressure ratio with acceptable efficiency.
In another word, tandem stage is capable having the same pressure ratio at lower rotational speed. The safe
operation domain and loss mechanism in tandem stage are also discussed in this report.





Unsteady Natural Convective Flow over an Impulsively Started SemiInfinite Vertical Plate in the Presence of Porous Medium with Chemical Reaction


Pages :
95102


Authors :
P. Loganathan,
C. Sivapoornapriya,
An investigation is carried out to analyze the effects of heat and mass transfer over an impulsively started
vertical plate in the presence of porous medium with chemical reaction. The unsteady, nonlinear, coupled
partial differential equations are solved by implicit finite difference scheme of Crank Nicolson type. The
influence of various parameters like Prandtl number, Schmidt number, first order chemical reaction on the
velocity, temperature and concentration are analyzed. The local skin friction, local Nusselt number, local
Sherwood number, average skin friction, average Nusselt number and average Sherwood numbers are
investigated. It is observed that the velocity and concentration boundary layer decreases with increasing
chemical reaction. An increase in the Schmidt number reduces the concentration boundary layer thickness.





Heat and Mass Transfer Effects on Unsteady MHD Natural Convection Flow of a Chemically Reactive and Radiating Fluid through a Porous Medium Past a Moving Vertical Plate with Arbitrary Ramped Temperature


Pages :
103117


Authors :
G. S. Seth,
R. Sharma,
B. Kumbhakar,
Investigation of unsteady hydromagnetic natural convection flow with heat and mass transfer of a viscous,
incompressible, electrically conducting, chemically reactive and optically thin radiating fluid past an
exponentially accelerated moving vertical plate with arbitrary ramped temperature embedded in a fluid
saturated porous medium is carried out. Exact solutions of momentum, energy and concentration equations
are obtained in closed form by Laplace transform technique. The expressions for the shear stress, rate of heat
transfer and rate of mass transfer at the plate for both ramped temperature and isothermal plates are derived.
The numerical values of fluid velocity, fluid temperature and species concentration are displayed graphically
whereas those of shear stress, rate of heat transfer and rate of mass transfer at the plate are presented in
tabular form for various values of pertinent flow parameters. It is found that, for isothermal plate, the fluid
temperature approaches steady state when t 1.5 . Consequently, the rate of heat transfer at isothermal plate
approaches steady state when t 1.5 .





Partition Effect on Thermo Magnetic Natural Convection and Entropy Generation in Inclined Porous Cavity


Pages :
119130


Authors :
H. Heidary,
M. J. Kermani,
M. Pirmohammadi,
In this study natural convection heat transfer fluid flow and entropy generation in a porous inclined cavity in
the presence of uniform magnetic field is studied numerically. For control of heat transfer and entropy
generation, one or two partitions are attached to horizontal walls. The left wall of enclosure is heated with a
sinusoidal function and right wall is cooled isothermally. Horizontal walls of the enclosure are adiabatic. The
governing equations are numerically solved in the domain by the control volume approach based on the
SIMPLE technique. The influence of Hartmann number, inclination angle, partition height, irreversibility
distribution ratio, and partition location is investigated on the flow and heat transfer characteristics and the
entropy generation. The obtained results indicated that the partition, magnetic field and rotation of enclosure
can be used as control elements for heat transfer, fluid flow and entropy generation in porous medium.





MHD Flow of Micropolar Fluid due to a Curved Stretching Sheet with Thermal Radiation


Pages :
131138


Authors :
M. Naveed,
Z. Abbas,
M. Sajid,
The twodimensional boundary layer flow of an electrically conducting micropolar fluid and heat transfer
subject to a transverse uniform magnetic field over a curved stretching sheet coiled in a circle of radius ܴ has
been studied. The effect of thermal radiation is also considered using linearized Rosseland approximation. For
mathematical formulation of the flow equations, curvilinear coordinates system is used. The governing partial
differential equations describing the flow phenomena and heat transfer characteristics are reduced to ordinary
differential equations by means of suitable transformations. The system of differential equations is solved
numerically by shooting method using RungeKutta algorithm combined with the NewtonsRaphson
technique. Some physical features of the flow and heat transfer in terms of fluid velocity, angular velocity,
temperature profile, the skinfriction coefficient, couple wall stress and the local Nusselt number for several
values of fluid parameters are analyzed, discussed and presented in graphs and tables. Comparison of the
present results with the published data for the flat surface i.e. (݇ → ∞) is found in good agreement.





Experimental Investigation on Electorhydrodynamically Enhanced Heat Transfer in Partially Open Enclosures


Pages :
139145


Authors :
F. Fazlollahi,
A. A. Alemrajabi,
Experimental investigation on heat transfer enhancement by applying electrohydrodynamics (EHD) in
partially open multiple fined enclosures with different aperture position has been performed. The enclosure
had five thermally and electrically insulated faces; while one face was copper finned plate with an aperture
located on its opposite face. In the present study, different parameters including electric current, number of
fins, aperture position, and corona polarity were investigated. It was concluded that heat transfer enhancement
is proportional to the supplied current. Higher number of fins can lead to further heat transfer enhancement
and as the location of aperture is shifted upward, the heat transfer coefficient is improved more significantly
by EHD.





Numerical Investigation of Mixed Convection Fluid Flow, Heat Transfer and Entropy Generation in Triangular Enclosure Filled with a Nanofluid


Pages :
147156


Authors :
A. Aghaei,
G. A. Sheikhzadeh,
H. Ehteram,
M. Hajiahmadi,
In this paper, mixed convection fluid flow, heat transfer and entropy generation inside a triangular enclosure
filled with CuOwater nanofluid with variable properties are investigated numerically. The inclined walls of
enclosure are maintained at a constant temperature Tc. The moving bottom wall is kept at a constant
temperature Th, which Th>Tc.The numerical simulation of mixed convection is carried out using a computer
program (FORTRAN language) based on finite volume method and SIMPLER algorithm. This study is
performed over a range of nanoparticle volume fractions(00.020.04) Richardson numbers(0.01, 0.1, 1, 10,
100), and angles of inclined walls(150, 300, 450, 600, 750) and a fixed Grashof number (Gr=104).In all
investigated aspect ratios and Richardson numbers, average Nusselt number increased by enhancement of
volume fraction till 0.02, but it is approximately constant by adding more nanoparticles till 0.04.It is also
observed that in all aspect ratios and Richardson numbers, the variation of total entropy generation by
enhancement of volume fraction is similar to Nusselt number.





Finite Difference Analysis of Unsteady MHD Free Convective Flow over Moving SemiInfinite Vertical Cylinder with Chemical Reaction and Temperature Oscillation Effects


Pages :
157167


Authors :
V. Rajesh,
O. Anwar Bég,
Ch. Sridevi,
In the present study, the effects of chemical reaction on unsteady free convection flow of a viscous,
electrically conducting, and incompressible fluid past a moving semiinfinite vertical cylinder with mass
transfer and temperature oscillation is studied. The dimensionless governing partial differential equations are
solved using an implicit finitedifference method of Crank–Nicolson type, which is stable and convergent.
The transient velocity, transient temperature, and transient concentration profiles are studied for various
parameters. The local as well as average skinfriction, Nusselt number, and Sherwood number are also
analyzed and presented graphically. The results are compared with available computations in the literature,
and are found to be in good agreement.





Unsteady/Steady Hydromagnetic Flow of Reactive Viscous Fluid in a Vertical Channel with Thermal Diffusion and Temperature Dependent Properties


Pages :
169176


Authors :
I. J. Uwanta,
M. M. Hamza,
The problem of unsteady as well as steady hydromagnetic natural convection and mass transfer flow of
viscous reactive, incompressible and electrically conducting fluid between two vertical walls in the presence
of uniform magnetic field applied normal to the flow region is studied. Thermal diffusion, temperature
dependent variable viscosity and thermal conductivity are assumed to exist within the channel. The governing
partial differential equations are solved numerically using implicit finite difference scheme. Results of the
computations for velocity, temperature, concentration, skin friction, rate of heat and mass transfer are
presented graphically to study the hydrodynamic behavior of fluid in the channel.





Towards a MultiDimensional Approach in Inflow and Outflow of Compressible Flows


Pages :
177183


Authors :
S. E. Razavi,
M. Taghilou,
A. Rezai,
A novel multidimensional characteristics approach for inflow and outflow boundaries of compressible twodimensional flows is presented. The modified Riemann variables have been extracted from the Euler
equations by considering the directions of waves reaching the inflow and outflow boundaries. By applying
this model in a shortened computational domain, the boundaries can be located close to the nonlinear zone.
The results of reduced and extended domains are in good agreement with each other. Using this model yields
in a reduction of computational domain while keeping the solution accuracy and lowering the computation
time.





Effects of Variant Positions of Cold Walls on Narural Convection in a Triangular Cavitiy


Pages :
185193


Authors :
M. Triveni,
R. Panua,
D. Sen,
The effect of different configurations of partial cold walls on laminar natural convection heat transfer for a
rightangle triangular cavity heated from below has been studied numerically. The enclosure is filled with
water and heat transfer surfaces such as hot and cold walls are maintained at constant temperature. The side
and hypotenuse walls of the enclosure are detached from the middle and have been arranged in four different
configurations, namely AB, BC, AD and CD for cooling purpose. The finite volume method is used to solve
the dimensionless governing mass, momentum and energy equations. The problem has been solved to explore
the effects of the pertinent parameters i.e. different configurations of cold walls and variation of Rayleigh
number (105 ≤ Ra ≤ 107). Results are obtained from numerical simulation using commercial software
package, FLUENT and presented in the form of streamlines and isotherms. The thermal performance of the
enclosure has been expressed by local and average Nusselt numbers. From the analysis, it is observed that the
temperature distribution and flow field are significantly affected by these parameters. The high heat transfer
rate has been observed for the position AB while low for the position CD. Also, the heat transfer rate
enhances as the Rayleigh number (Ra) increases.





Diffusion of Chemically Reactive Species in StagnationPoint Flow of a Third Grade Fluid: a Hybrid Numerical Method


Pages :
195203


Authors :
Z. Abbas,
T. Javed,
N. Ali,
M. Sajid,
The boundary layer flow of a third grade fluid and mass transfer near a stagnationpoint with diffusion of
chemically reacting species on a porous plate is investigated. Due to a porous plate the suction is taken into an
account. Using suitable transformations, the momentum and concentration equations are first transformed into
nonlinear ordinary ones and then solved using a hybrid numerical method. This method combines the features
of finite difference and shooting methods. The effects of various controlling parameters on the flow velocity,
concentration profile, skin friction and rate of mass transfer on surface are analyzed graphically and in tabular
form. Comparison of the present results with the previous reported results has been found in excellent
agreement.





MagnetoHydrodynamic Flow in a TwoDimensional Inclined Rectangular Enclosure Heated and Cooled on Adjacent Walls


Pages :
205213


Authors :
N. M. Kherief,
F. Berrahil,
K. Talbi,
Steady, laminar, naturalconvection flow in the presence of a magnetic field in an inclined rectangular
enclosure heated from one side and cooled from the adjacent side was considered. The governing equations
were solved numerically for the stream function, vorticity and temperature using the finitevolume method for
various Grashof and Hartman numbers and inclination angles and magnetic field directions. The results show
that the orientation and the strength and direction of the magnetic field have significant effects on the flow
and temperature fields. Counterclockwise inclination induces the formation of multiple eddies inside the
enclosure significantly affecting the temperature field. Circulation inside the enclosure and therefore the
convection become stronger as the Grashof number increases while the magnetic field suppresses the
convective flow and the heat transfer rate.





ThreeDimensional MHD Flow of Casson Fluid in Porous Medium with Heat Generation


Pages :
215223


Authors :
S. A. Shehzad,
T. Hayat,
A. Alsaedi,
The magnetohydrodynamic (MHD) threedimensional boundary layer flow of an incompressible Casson fluid
in a porous medium is investigated. Heat transfer characteristics are analyzed in the presence of heat
generation/absorption. Laws of conservation of mass, momentum and energy are utilized. Results are
computed and analyzed for the velocities, temperature, skinfriction coefficients and local Nusselt number.





Ohmic Heating and Viscous Dissipation Effects over a Vertical Plate in the Presence of Porous Medium


Pages :
225232


Authors :
P. Loganathan ,
C. Sivapoornapriya,
An analysis is performed to investigate the ohmic heating and viscous dissipation effects on an unsteady
natural convective flow over an impulsively started vertical plate in the presence of porous medium with
radiation and chemical reaction. Numerical solutions for the governing boundary layer equations are
presented by finite difference scheme of the Crank Nicolson type. The influence of various parameters on the
velocity, the temperature, the concentration, the skin friction, the Nusselt number and the Sherwood number
are discussed. It is observed that velocity and temperature increases with increasing values of permeability
and increasing values of Eckert number, whereas it decreases with increasing values of magnetic parameter.
An increase in ohmic heating and viscous heating increases the velocity boundary layer. An increase in ohmic
heating decreases the temperature. An increase in magnetic field reduces the temperature profile. The velocity
profile is highly influenced by the increasing values of permeability. It is observed that permeability has
strong effect on velocity. An enhancement in ohmic heating increases the shear stress, decreases the rate of
heat transfer and induces the rate of mass transfer.





Unsteady Compressible Flow Calculations with LeastSquare Meshless Method


Pages :
233241


Authors :
S. Sattarzadeh,
A. Jahangirian,
M. Y. Hashemi,
A dualtime implicit meshless method is presented for unsteady compressible flow calculations. Polynomial
leastsquare (PLS) and Taylor series leastsquare (TLS) procedures are used to estimate the spatial derivatives
at each node and their computational efficiencies are compared. Also, the effect of the neighbor stencil
selection on the accuracy of the method is investigated. As a new approach, different neighboring stencils are
used for the highly stretched point distribution inside the boundary layer region and the inviscid isotropic
point distribution outside this area. The unsteady flows over stationary and moving objects at subsonic and
transonic flow conditions are solved. Results indicate the computational efficiency of the method in
comparison with the alternative approaches. The convergence histories of the flow solution show that the PLS
method is computationally faster than TLS method. In addition, the eight point neighboring stencil inside the
viscous region is more efficient than other choices.





Influence of Types of Steel Poles on Measurements by Wind Speed Sensors along HighSpeed Railways


Pages :
243251


Authors :
J. Zhang,
G. Gao,
X. Xiong,
T. Liu,
F. Liu,
To find the influence of different types of steel poles on measurements by wind speed sensors along highspeed railways, the threedimensional Reynoldsaveraged NavierStokes equations, combined with the kε
turbulence model, were solved on an unstructured grid with a boundary layer using the finite volume method.
The gridindependent validation was firstly conducted, and the accuracy of the present numerical simulation
method was validated by experiments and simulations carried out by previous researchers. To ascertain angles
of influence at different distances between the sensor and the virtual one, the flow field around a sensor was
investigated with the method of altering the relative coordinates between the two sensors. After that, the flow
fields and velocity distributions around steel poles were studied. It can be stated that behind the sensor, the
closer the distance from the sensor center line, the larger the angle of influence. However, as the distance is
varied from 0.3 to 1.0 m, the most adverse angles are not in excess of ±20°. In addition, the steel poles have a
certain influence on the measurement results of sensors. A “twosided petal acceleration region” with a
“central pistil deceleration zone” comes into being. From the perspective of regions of influence in different
wind directions, the influence region of the annulus pole is basically the same. For the square and H types,
when the angle is 45°, the region of effect is the largest. For the same distance between the sensor and the
pole, the space required between two sensors for the single H type is larger than that required by the annulus
type. Thus, it is suggested that the distance between sensors and the pole should be 1.0 m with the
anemometer located on the upstream side, and the distance between two anemometers should be 0.8 m.





Numerical Investigation in the Vaned Distributor under Different Guide Vanes Openings of a Pump Turbine in Pump Mode


Pages :
253266


Authors :
D. Y. Li,
R. Z. Gong,
H. J. Wang,
J. Zhang,
X. Z. Wei,
L. F. Shu,
The performance of a pump turbine in pump mode is of great importance to a pumped storage power plant. In
order to obtain the pump characteristics of a pump turbine, 3D steady simulations were carried out by solving
rans using different twoequation turbulence models. Compared with the experimental data, SST kω
turbulence model was chosen to simulate external characteristics curves under 32mm, 22mm and 18mm guide
vanes openings. The results show a good agreement with the experimental data, especially near the best
efficiency point. Finally, the detailed analysis was conducted within vaned distributor for these three guide
vanes openings. The variation of flow field, pressure filed, energy characteristic and loss with the discharge
and guide vanes opening were obtained through the analysis. This research could provide a basic
understanding on pump characteristics of a pump turbine for designer.





Thermal Radiation Effects on MHD Boundary Layer Slip Flow Past a permeable Exponential Stretching Sheet in the Presence of Joule Heating and Viscous Dissipation


Pages :
267278


Authors :
P. Sreenivasulu,
T. Poornima,
N. Bhaskar Reddy,
An analysis of the thermal radiation effects on MHD boundary layer flow past a permeable exponential
stretching surface in the presence of Joule heating and viscous dissipation is presented. Velocity and thermal
slips are considered instead of noslip conditions at the boundary. Stretching velocity and wall temperature
are assumed to have specific exponential function forms. The governing system of partial differential
equations is transformed into a system of ordinary differential equations using similarity transformations and
then solved numerically using the RungeKutta fourth order method along with shooting technique. The
effects of the various parameters on the velocity, shear stress, temperature and temperature gradient profiles
are illustrated graphically and discussed in detail. The influence of the slip parameters causes significant
fluctuations in velocity of the flow field. Viscous dissipation characterized by Eckert number enhances the
temperature of the fluid, as the heat gets transferred from the sheet to the fluid.





Investigation of Fire Growth and Spread in a ModelScale Railcar Using an Applied Approach


Pages :
279292


Authors :
A. Kazemipour,
M. Pourghasemi,
H. Afshin,
B. Farhanieh,
Fire is a potential hazard in public transportation facilities such as subways or road tunnels due to
its contribution to high number of deaths. To provide an insight into fire development behavior in
tunnels which can serve as the basis for emergency ventilation design, modelscale railcar fire is
explored numerically in this research. Fire growth and its spread are investigated by analyzing the
HRR curve as the representative of fire behavior in different stages. Fire development has been
predicted through a new approach using an Arrheniusbased pyrolysis model, established to
predict the decomposition behavior of solid flammable materials exposed to heat flux. Using this
approach, modelscale railcar fire curve is obtained and compared with experimental data.
Reasonable agreement is achieved in two important stages of flashover and fully developed fire,
confirming the accuracy of the presented approach. Moreover, effects of railcar material type,
amount of available air, and surrounding are also discussed. Detailed illustrations of physical
phenomena and flow structures have been provided and justified with experimental findings for
better description of railcar fire behavior. The presented approach can be further used in other
applications such as investigation of fire spread in a compartment, studying fire spread from a
burning vehicle to another and reconstruction of fire incidents.





A Study on Mixed Convective, MHD Flow from a Vertical Plate Embedded in NonNewtonian Fluid Saturated Non Darcy Porous Medium with Melting Effect


Pages :
293302


Authors :
J. Siva Ram Prasad,
K. Hemalatha,
We analyzed in this paper the problem of mixed convection along a vertical plate in a nonNewtonian fluid
saturated nonDarcy porous medium in the presence of melting and thermal dispersionradiation effects for
aiding and opposing external flows. Similarity solution for the governing equations is obtained for the flow
equations in steady state. The equations are numerically solved by using Rungekutta fourth order method
coupled with shooting technique. The effects of melting (M), thermal dispersion (D), radiation (R), magnetic
field (MH), viscosity index (n) and mixed convection (Ra/Pe) on fluid velocity and temperature are examined
for aiding and opposing external flows.





Aided Mixed Convection past a Heated Square Cylinder at Low Blockage Ratio


Pages :
303310


Authors :
S. Moulai,
A. Korichi,
G. Polidori,
This paper investigates numerically the flow and heat transfer in air (Pr=0.71) by mixed convection past a
heated square cylinder under aiding buoyancy effect in a confined channel. The numerical simulations are
performed in the range of parameters 20≤Re≤45 and 1.61x103≤Gr≤6.33x103 for a fixed blockage ratio D/L of
0.1. The combination in the present study of these two Re and Gr parameters is reduced so that the Richarson
number varies from 0,8 to 8, in order to neglect neither free convection (Ri<0.1) nor forced convection
(Ri>10). The steady twodimensional governing equations are solved by the finite volume formulation using
the open source OpenFoam® code. The representative flow structure, isotherm patterns and local Nusselt
number evolution are presented and discussed. The effect of both the Reynolds number and the buoyancy
parameter on the fluid flow and the heat transfer are also analyzed. It is found that the wake region size
strongly depends on both Reynolds and Grashof numbers and this region is shown to increase in size
increasing the Reynolds number and/or decreasing the Grashof number. Moreover, increasing the Reynolds
number leads to a heat transfer enhancement more pronounced on the front face of the obstacle, whereas
increasing the Grashof number leads to a heat transfer enhancement more pronounced on the side faces.





A Numerical Simulation on MHD Mixed Convection in a Liddriven Cavity with Corner Heaters


Pages :
311319


Authors :
A. Malleswaran,
S. Sivasankaran,
A numerical investigation on mixed convection in a liddriven square cavity has been performed in the
presence of the uniform magnetic field. From the leftbottom corner of the cavity, three different lengths of
heater are varied along bottom and left walls simultaneously. The finite volume method is employed to solve
the governing equations. It is observed that the heater length in the xdirection is more effective than that of in
the ydirection on the heat transfer and on the flow pattern. The magnetic field affects the average heat
transfer rate more on vertical heaters than on the horizontal heaters.





MHD Flow Heat and Mass Transfer of Micropolar Fluid over a Nonlinear Stretching Sheet with Variable Micro Inertia Density, Heat Flux and Chemical Reaction in a Nondarcy Porous Medium


Pages :
321331


Authors :
S. Rawat,
S. Kapoor,
R. Bhargava,
This paper investigates the two dimensional flow, heat and mass transfer of chemically reacting Micropolar
fluid over a nonlinear stretching sheet with variable heat flux in a nondarcy porous medium. The rate of
chemical reaction is assumed to be constant throughout the fluid i.e. homogenous. Using a similarity
transformation, the governing partial differential equations are transformed into a system of ordinary
differential equation, which is then solved using Finite element method. Numerical results regarding local
Nussult No. are shown graphically with Magnetic number (ܰ݉௫) for variation in heat transfer exponent (n).
This study also analyzes the effect of velocity exponent m, heat transfer exponent n, material parameter K,
Magnetic Number(ܰ݉௫)Darcy NumberDax, Forchheimer Number Nfx, Prandtl number Pr, Schmidt Number
Sc and Chemical reaction rate parameter x on velocity, microrotation, temperature and concentration
profiles. Velocity exponent m has a positive effect on the velocity, temperature and concentration profiles
while microrotation decreases as m increases. Graphical results shows that the thermal boundary layer
thickness decreases at and near the wall with the increase in heat flux exponent n. Also an increase in K leads
to a decrease in skin friction parameter as well as the wall couple stress.





Numerical Study of Water Production from Compressible MoistAir Flow


Pages :
333341


Authors :
S. Hamidi,
M. J. Kermani,
In this research a numerical study of water production from compressible moistair flow by condensing of the
vapor component of the atmospheric air through a convergingdiverging nozzle is performed. The
atmospheric air can be sucked by a vacuum compressor. The geographical conditions represent a hot and
humid region, for example Bandar Abbas, Iran, with coordinates, 270 11 ’ N and 560 16’ E and summer climate
conditions of about 40℃and relative humidity above 80%. Parametric studies are performed for the
atmosphericair temperature between, 40℃ to 50℃, and relative humidity between49.6% to 100.%. For these
ranges of operating conditions and a nozzle with the area ratio of 1.17, the liquid mass flow rates falls in the
range 0.272 to 0.376 kg/s. The results show that, the energy consumed by the compressor for production 1 kg
of water will be 1.279 kWh. The price of 1 kWh is 372 Rials, therefore the price for the production of 1 kg
liquid water will be 475.8 Rials, therefore, the scheme is economically suitable.





Numerical Solutions of Free Convective Flow from a Vertical Cone with Mass Transfer under the Influence of Chemical Reaction and Heat Generation/Absorption in the Presence of UWT/UWC


Pages :
343356


Authors :
B. Pullepu,
P. Sambath,
M. Selva Rani ,
A. J. Chamkha,
K. K. Viswanathan,
The purpose of this paper is to present a mathematical model for the combined effects of chemical reaction
and heat generation/absorption on unsteady laminar free convective flow with heat and mass transfer over an
incompressible viscous fluid past a vertical permeable cone with uniform wall temperature and concentration
(UWT/UWC).The dimensionless governing boundary layer equations of the flow that are transient, coupled
and nonlinear partial differential equations are solved by an efficient, accurate and unconditionally stable
finite difference scheme of CrankNicholson type. The velocity, temperature, and concentration profiles have
been studied for various parameters viz., chemical reaction parameter , the heat generation and absorption
parameter , Schmidt number Sc , Prandtl number Pr , buoyancy ratio parameter N . The local as well as
average skin friction, Nusselt number, Sherwood number, are discussed and analyzed graphically. The present
results are compared with available results in open literature and are found to be in excellent agreement





Numerical Study of Cavitation in Francis Turbine of a Small Hydro Power Plant


Pages :
357365


Authors :
P. P. Gohil,
R. P. Saini,
Cavitation is undesirable phenomena and more prone in reaction turbines. It is one of the challenges in any
hydro power plant which cause vibration, degradation of performance and the damage to the hydraulic turbine
components. Under the present study, an attempt has been made to carry out a numerical analysis to
investigate the cavitation effect in a Francis turbine. Three dimensional numerical study approach of unsteady
and SST turbulence model are considered for the numerical analysis under multiphase flow such as cavitating
flow. The performance parameters and cavitating flow under different operating conditions have been
predicted using commercial CFX code. Three different operating conditions under cavitation and
without cavitation with part load and overload conditions of the turbine for a plant sigma factor are
investigated. The results are presented in the form of efficiency, pressure fluctuation, vortex rope and vapor
volume fraction.
It has been observed that variation in efficiency and vapor volume fraction is found to be nominal between
cavitation and without cavitation conditionsat rated discharge and rated head. Turbine efficiency loss and
vapor bubbles formation towards suction side of the runner blade are found to be maximum under overload
condition. However, the pressure pulsation has been found maximum under part load condition in the draft
tube. The simulation results are found to be in good agreement with model test results for efficiency. The
locations of cavitating zone observed wellwith the result of previous studies.





Investigation of Nonlinear Electrokinetic and Rheological Behaviors of Typical NonNewtonian Biofluids through Annular Microchannels


Pages :
367378


Authors :
A. Hamedi,
M. Shamshiri,
M. Charmiyan,
E. Shirani,
Electroosmosis is the predominant mechanism for flow generation in labonchip devices. Since most
biofluids encountered in these devices reveal nonNewtonian behavior, a special understanding of the
fundamental physics of the relevant transport phenomena seems vital for an accurate design of such
miniaturized devices. In this study, a numerical analysis is presented to explore transport characteristics of
typical nonNewtonian biofluids through annular microchannels under combined action of pressure and
electrokinetic forces. The flow is considered steady and hydrodynamically fully developed. A finite
difference method is used to solve the PoissonBoltzmann and Cauchy momentum equations, while the
classical boundary condition of no velocityslip for the flow field is applied. The PoissonBoltzmann equation
is solved in the exact form without using the DebyeHückel approximation. After numerically solving the
governing equations, role of the key parameters in hydrodynamic behavior of the flow is analyzed and
discussed.





Effect of Chemical Reaction on Convective Heat Transfer of Boundary Layer Flow in Nanofluid over a Wedge with Heat Generation/Absorption and Suction


Pages :
379388


Authors :
R. M. Kasmani,
S. Sivasankaran,
M. Bhuvaneswari,
Z. Siri,
The aim of the present study is to examine the convective heat transfer of nanofluid past a wedge subject to
firstorder chemical reaction, heat generation/absorption and suction effects. The influence of wedge angle
parameter, thermophoresis, Dufour and Soret type diffusivity are included. The local similarity transformation
is applied to convert the governing nonlinear partial differential equations into ordinary differential equations.
Shooting method integrated with fourthorder RungeKutta method is used to solve the ordinary differential
equations. The skin friction, heat and mass transfer rates as well as the effects of various parameters on
velocity, temperature and solutal concentration profiles are analyzed. The results indicate that when the
chemical reaction parameter increases, the heat transfer coefficient increases while the mass transfer
coefficient decreases. The effect of chemical reaction parameter is very important in solutal concentration
field compared to velocity and temperature profiles since it decreases the solutal concentration of the
nanoparticle.





Numerical Analysis for Peristaltic Motion of MHD EyringPrandtl Fluid in an Inclined Symmetric Cannel with Inclined Magnetic Field


Pages :
389396


Authors :
F. A. Abbasi,
T. Hayat,
A. Alsaedi,
This article addresses the peristaltic transport of EyringPrandtl fluid in an inclined asymmetric channel. Heat
and mass transfer phenomena along with Soret and Dufour effects is analyzed. Effects of inclined magnetic
field and Joule heating are also discussed. Long wavelength approximation is adopted. Numerical
computations for flow quantities of interest are analyzed. It is found that the parabolic velocity profile tends
to shift from center of the channel towards the channel walls in the case of opposing flow. Velocity and
temperature decrease whereas concentration increases by increasing the nonNewtonian parameter. Further
the dependence of magnetic field on the angle is quite significant





Experimental Study of Plasma Actuator Effects on Flow Field Separation Bubble around Blunt Flat Plate


Pages :
397406


Authors :
S. Kavousfar,
E. Esmaeilzadeh,
H. MahdavyMoghaddam,
M. Mirzaei,
S. G. Pouryoussefi,
In this paper, the air flow around a blunt flat plate with a rounded leading edge has been experimentally
examined with and without the presence of a plasma actuator. Tests have been conducted with Reynolds
numbers ranging from 104 to 105. Significant phenomena in this flow field is the flow separation at the
leading edge of the body, which called separation bubble. There are two considerably dimensionless
parameters in this experiment. One of them is the leading edge radius ratio to body thickness and other one is
the ratio of maximum velocity induced by plasma actuator to free stream velocity. Geometries with the values
of R/D=0, 1/16, 2/16, 4/16 were tested. For each geometry, the effectiveness of plasma actuator on the
separation bubble is studied in different values of velocity ratio. The results show that, the effect of plasma
actuator for the geometry with sharp edge (R/D=0), is negligible, while in geometry with rounded edge, the
plasma actuator has significant effect on the separation bubble domain. This effectiveness is enhanced, by
increasing of leading edge radius and velocity ratio, so that in rounded edge geometry (R/D=4/16) length of
separation bubble is reduced about 75%.





Radial and Axial Magnetic Fields Effects on Natural Convection in a Nanofluidfilled Vertical Cylinder


Pages :
407418


Authors :
M. Battira,
R. Bessaïh,
This work aims to study numerically the steady natural convection in a vertical cylinder filled with an Al2O3
nanofluid under two different external magnetic fields (Br, Bz) either in the radial or axial directions. The
cylinder having an aspect ratio H/R0=1 is bounded by the top and the bottom disks at temperatures Tc and Th,
and by an adiabatic side wall. The equations of continuity, NavierStokes and energy are nondimensionalized
and then discretized by the finite volume method. A computer program based on the SIMPLER algorithm is
developed and compared with the numerical results found in the literature. The effects of nanosize solid
volume fraction ranging from 0 to 0.1 and application of the magnetic field in either directions axial and
radial for various values of Hartmann numbers on flow and thermal fields, and on local and average Nusselt
numbers are presented and discussed for two values of Rayleigh numbers (Ra=103 and 104). The behaviors of
average Nusselt number, streamlines, temperature contours, and the both components of velocity are
illustrated. The results indicate that for small values of the Hartmann number, where the flow remains due to
the convection, the average Nusselt number decreases when increasing the solid volume fraction and this
decrease is more important if the magnetic field is applied in the axial direction and by increasing the
Hartmann numbers. The increasing in the solid volume fraction increases the performance of heat transfer in
the nanofluid.





Applied Thermal Lattice Boltzmann Model for Fluid Flow of Free Convection in 2D Enclosure with Localized Two Active Blocks: Heat Transfer Optimization


Pages :
419430


Authors :
T. Naffouti,
J. Zinoubi,
N. A. Che Sidik ,
R. B. Maad,
The aim of this paper is to analyze the laminar free convective flow generated by two identical hot blocks in
twodimensional enclosure cooled by the sides in order to optimize the heat transfer. The top wall and the flat
surfaces on bottom wall are adiabatic except for the active sources located symmetrically. Each source of a
rectangular form is heated at a uniform temperature while the Prandtl number is fixed at 0.71. Thermal Lattice
Boltzmann model of D2Q4D2Q9 is applied to solve the thermal flow problem. Numerical simulations have
been conducted to reveal the effects of various parameters; Rayleigh number 103 ≤ Ra ≤ 106, spacing between
blocks 0.1 ≤ D ≤ 0.6, block height 0.05 ≤ H ≤ 0.4 and aspect ratio of the enclosure 1 ≤ A ≤ 4 on fluid flow and
heat transfer. The computational results by Lattice Boltzmann method have been found to be in good
agreement with previous works. The results are presented in the form of isotherms and streamlines plots as
well as the variation of the average Nusselt number along horizontal and vertical hot walls. It is found that
increasing Rayleigh number and distance between active blocks enhance the heat transfer. The simulations
show that the block height and aspect ratio are the most important parameters affecting dynamic and thermal
fields and consequently the heat transfer efficiency in the enclosure.





Numerical Simulation of NonNewtonian Core Annular Flow through Rectangle Return Bends


Pages :
431441


Authors :
F. Jiang,
Y. Long,
Y. J. Wang,
Z. Z. Liu,
C. G. Chen,
The volume of fluid (VOF) model together with the continuum surface stress (CSS) model is proposed to
simulate the core annular of nonNewtonian oil and water flow through the rectangle return bends (∏bends).
A comprehensive investigation is conducted to generate the profiles of volume fraction, pressure and velocity.
The influences of oil properties, flow direction, and bend geometric parameters on hydrodynamic of nonNewtonian oil and water core annular flow in ∏bends are discussed. Through computational simulations the
proper bend geometric parameters were identified, these results are useful for designing and optimizing the
pipefitting system.





Numerical Simulation of the Flow Field around Generic Formula One


Pages :
443450


Authors :
D. TienPhuc,
G. ZhengQi,
C. Zhen,
The steady ReynoldsAveraged NavierStokes (RANS) method with the Realizable k turbulence model
was used to analyze the flow field around a race car (generic Formula One). This study was conducted using
the ANSYS software package. The numerical simulations were conducted at a Reynolds number based on the
race car model (14.9×106). The timeaveraged velocity field, flow topology, velocity magnitude, static
pressure magnitude and vortex regions of the flow fields are presented in this paper. The measurements were
performed on the vertical and crosssectional planes. The results are presented graphically, showing the main
characteristics of the flow field around the whole race car, whereas most previous studies only mention the
flow field around individual components of race cars. The Realizable k turbulence model results showed
consistency with the valuable validation data, which helps to elucidate the flow field around a model generic
Formula one race car.





Investigation of ThreeDimensional Axisymmetric Unsteady StagnationPoint Flow and Heat Transfer Impinging on an Accelerated Flat Plate


Pages :
451461


Authors :
A. Shokrgozar ,
A. B. Rahimi,
H. Mozayeni,
General formulation and solution of NavierStokes and energy equations are sought in the study of threedimensional axisymmetric unsteady stagnationpoint flow and heat transfer impinging on a flat plate when the
plate is moving with variable velocity and acceleration towards the main stream or away from it. As an
application, among others, this accelerated plate can be assumed as a solidification front which is being
formed with variable velocity. An external fluid, along z  direction, with strain rate a impinges on this flat
plate and produces an unsteady threedimensional axisymmetric flow in which the plate moves along z direction with variable velocity and acceleration in general. A reduction of NavierStokes and energy
equations is obtained by use of appropriate similarity transformations, for the first time. The obtained
ordinary differential equations are solved by using finitedifference numerical techniques. Velocity and
pressure profiles along with temperature profiles are presented for different examples of the plate velocity
functions and selected Prandtl numbers. According to the results obtained, the velocity and thermal boundary
layers feel the effect of variations of the plate velocity more than the plate acceleration. It means that the
minimum boundary layer thickness happens at the maximum value of the plate velocity and acceleration
effect plays a secondary role.





Forced Convective Flow of a Nanoliquid due to a Stretching Cylinder with Free Stream


Pages :
463474


Authors :
D. Sinha,
P. Jain,
P. G. Siddheshwar,
N. S. Tomer,
Steady, transverse boundary layer flow and heat transfer caused by an exponentially stretching cylinder of
constant radius immersed in an uniform flow of an incompressible, viscous nanoliquid are considered in
the present study. The paper discusses a systematic procedure of obtaining a local similarity transformation
that reduces the governing partial differential equations into ordinary differential equations. Power series
solution is then obtained for velocity, temperature and nanoparticle concentration distributions using the
univariate differential transform method. Help is sought from DombSykes plots in making a decision on
the minimum number of terms required in the power series expansion to ensure convergence. Radius of
convergence is quite naturally suggested by these plots. Pad ´ e approximants are then appropriately decided
upon to increase the radius of convergence. The algorithm used succeeds in capturing boundary effects, free
stream flow effects and nanoparticle effects on flow and heat transfer. An important finding of the paper is
the prediction of accelerated cooling of the stretching cylinder due to the nanoparticles in the cooling liquid.
In having a desirable property for the extruding cylinder nanoliquid coolant seems an attractive proposition.





Effects of Thermophoresis, Dufour, Hall and Radiation on an Unsteady MHD Flow past an Inclined Plate with Viscous Dissipation, Chemical Reaction and Heat Absorption and Generation


Pages :
475485


Authors :
N. Pandya,
A. K. Shukla,
This paper investigates study of MHD(Magnetohydrodynamics) flow of viscous incompressible fluid past
an inclined porous plate embedded in porous medium with the effects of Thermophoresis, Dufour, Hall,
radiation, viscous dissipation, chemical reaction and heat generation or absorption. Non dimensional partial
differential equations of governing equations of flow are solved numerically by applying CrankNicolson
finite difference method for different values of parameters. Velocity, temperature, concentration profiles are
discussed through graphs for different values of parameters and skin friction coefficients, Nusselt number
and Sherwood number are discussed through tables.





CFD Simulations of Pressure Drop and Velocity Field in a Cyclone Separator with Central Vortex Stabilization Rod


Pages :
487499


Authors :
J. J. H. Houben,
Ch. Weiss,
E. Brunnmair,
S. Pirker,
A problem of cyclone separators is the low grade efficiency of small particles. Therefore, a high efficiency
cyclone separator has been developed and successfully tested in former work. In this cyclone separator, a
vortex stabilizer is used to suppress the vortex core precession. In this article, the pressure and flow field
in this cyclone separator are calculated by means of computational fluid dynamics using the commercial
software Ansys Fluent 13. The position of the vortex core is tracked in these simulations by searching the
position of minimal dynamic pressure and the centre of moment of the horizontal velocity components as
function of the axial coordinate. The results are compared with experimental data. It is demonstrated that
when using a stabilizer, the vortex is kept in position. Furthermore the maximum of the tangential velocity
is found to be larger, which is known to have a positive effect on the separation of small particles in the
inner solid body rotation vortex.





Flow of Two Immiscible Couple Stress Fluids between Two Permeable Beds


Pages :
501507


Authors :
J. Srinivas,
J. V. Ramana Murthy,
The paper deals with the flow of two immiscible couple stress fluids between two homogeneous permeable
beds. The flow is considered in two zones: zone I and II contain free flow of two immiscible couple stress
fluids between two permeable porous beds at the bottom and top. The flow in the free channel bounded by
two permeable beds is assumed to be governed by Stokes’s couple stress fluid flow equations and that in
the permeable beds by Darcy’s law. The continuity of velocity, vorticity, shear stress and couple stress are
imposed at the fluidfluid interface and BeaversJoseph (BJ) slip boundary conditions are employed at the
fluidporous interface. The equations are solved analytically and the expressions for velocity, skin friction
and volumetric flow rate are obtained. The effects of the physical governing parameters on velocity are
investigated.





The Transient MHD Flow Generated by a PeriodicWall Motion in a Porous Space


Pages :
509517


Authors :
M. Abdulhameed,
H. Saleh,
I. Hashim,
R. Roslan,
The problem of transient flow of incompressible third grade fluid on the twodimensional magnetohydrodynamic
(MHD) flow in a porous space is analyzed. The flow is generated due to the motion of the plate in
its plane with a periodic velocity. Under the flow assumptions, the governing nonlinear partial differential
equation is transformed into steadystate and transient nonlinear equations. The reduced equation for the
transient flow is solved analytically using symmetry approach while the nonlinear steadystate equation is
solved using a modified version of He’s homotopy perturbation method. The effect of several operating parameters
on the flow hydromagnetic is discussed. The results indicated that for the considered case, t = 1:5
is the moment after which the timedependent transient motion of the fluid can be approximated with the
steadystate motion, described by the steadystate solution. It is clear that, after this value of time t the
timedependent transient solution can be neglected.





