Journal of Applied Fluid MechanicsJAFMMechanical Engineeringhttp://jafmonline.net1admin173535721735364510.18869/acadpub.jafmenjalali1395411gregorian20167195online1fulltexten10.18869/acadpub.jafm.68.236.25622Effect of Variable Gravity on Darcy Flow with Impressed Horizontal Gradient and Viscous DissipationgeneralResearchThe effect of variable gravity on the free convection in a horizontal porous layer with viscous dissipation
is investigated. The bottom boundary is taken as adiabatic and there is a non-uniform
temperature distribution along the upper boundary. The effect of viscous dissipation is signiﬁcant
and the top boundary temperature distribution is assumed to have a constant gradient. The gravity
varies linearly with the height. A linear stability analysis of the basic ﬂow is carried out. The critical
horizontal Rayleigh number is calculated for oblique roll disturbances. The longitudinal rolls are
found to be the most unstable ones. The viscous dissipation has a destabilizing effect. There is a
drastic decrease in the value of critical horizontal Rayleigh number when modiﬁed variable gravity
parameter changes from 1 to 1.Darcy ﬂow; Variable gravity; Viscous dissipation.26212628http://jafmonline.net/JournalArchive/download?file_ID=40919&issue_ID=236KamalikaRoykomolika.roy89@gmail.com`YesIIT Kharagpur`

`P. V. S. N.Murthypvsnm@maths.iitkgp.ernet.in``NoDepartment of mathematics, Indian Institute of Technology Kharagpur, India`