Journal of Applied Fluid MechanicsJAFMMechanical Engineeringhttp://jafmonline.net1admin173535721735364510.29252/jafmenjalali1398610gregorian201991125online1fulltexten10.29252/jafm.12.05.29335Effect of Knudsen Number, Lid Velocity and Velocity Ratio on Flow Features of Single and Double Lid Driven CavitiesgeneralResearchEffects of Knudsen number, lid velocity and velocity ratio are investigated on the flow features of single lid driven cavity with an aspect ratio of one and double lid driven cavity of aspect ratio two. Knudsen numbers studied are 0.01(early slip regime), 0.1 (slip regime) and 1 (transitional regime). Lid velocities investigated are 100 m/s, 200 m/s and 500 m/s. The velocity ratios explored are 1 and -1. Knudsen number was found to have a huge impact on the flow rigidity. Lid velocity tends to shift the central vortex to the top left of the cavity for a cavity with aspect ratio of one and shifts the upper vortex to the top left of the cavity for a cavity with aspect ratio of two. Lid velocity does not affect the slip to a great extent on the lid. Changing the velocity ratio from 1 to -1 leads to the reversal of the relative vorticity in the top and bottom half of the cavity.Rarefied gas dynamics; DSMC; OpenFOAM; MEMS/NEMS.15751583http://jafmonline.net/JournalArchive/download?file_ID=49814&issue_ID=1002S.Mukherjeeswarnava_mukherjee@yahoo.co.in`NoDepartment of Mechanical Engineering, Amrita School of Engineering, Coimbatore, Amrita Vishwa Vidya`

`V.Shahabiv.shahabi69@gmail.com``NoHigh Performance Computing (HPC) Laboratory, Department of Mechanical Engineering, Ferdowsi Univers`

`R.Gowthamrajjgowtham32@gmail.com``NoDepartment of Mechanical Engineering, Amrita School of Engineering, Coimbatore, Amrita Vishwa Vidya`

`K. S.Rajanskashrajan@gmail.com``NoDepartment of Mechanical Engineering, Amrita School of Engineering, Coimbatore, Amrita Vishwa Vidya`

`R. K.Velamativ_ratnakishore@cb.amrita.edu``YesDepartment of Mechanical Engineering, Amrita School of Engineering, Coimbatore, Amrita Vishwa Vidya`