ACTA TECHNICA CORVINIENSIS - Bulletin of Engineering

ACTA TECHNICA CORVINIENSIS – BULLETIN of ENGINEERINGSkin friction3.532.521.51Figure 9. Skin friction when Gamma=0.5,K=0.5,M=1,Gr=5M=3,Gr=5M=5,Gr=5M=1,Gr=-5M=3,Gr=-5M=5,Gr=-5G r(Thermal grashof number) for cooling of theporous plate. But the reverse effect is observed inthe case of heating of the porous plate.Skin friction5432Figure 12. Skin friction when M=1,Gamma=0.5,K=0.5Gr=2Gr=5Gr=10Gr=-2Gr=-5Gr=-100.50.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1t3.53Figure 10. Skin friction when M=1,K=0.5,10-10.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1tSkin friction2.521.510.5Gamma=0.1,Gr=5Gamma=0.5,Gr=5Gamma=1, Gr=5Gamma=0.1,Gr=-5Gamma=0.5,Gr=-5Gamma=1, Gr=-5ACKNOWLEDGEMENTSI acknowledge with gratitude, the help andconstructive criticism offered by Dr. S. Vijayakumar varma, Professor of Mathematics,S.V.University, Tirupati (A.P), India, in the abovework.Skin friction00.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1t43.532.521.51Figure 11. Skin friction when M=1,Gamma=0.5,K=0.1,Gr=5K=0.3,Gr=5K=0.5,Gr=5K=0.1,Gr=-5K=0.3,Gr=-5K=0.5,Gr=-50.50.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1tThe skin friction is presented in figures (9) to(12). From these figures we conclude that theskin-friction increases with increase in M(Magnetic parameter) and γ (suctionparameter), but decreases with an increase in K(permeability parameter) for both cooling andheating of the porous plate. It is also observedthat skin-friction decreases with increase inNomenclatureA Constanty′ Coordinate axis normal to the platey Dimensionless coordinate axis normal to theplateu Dimensionless velocityB External magnetic field0PrCpPrandtl numberSpecific heat at constant pressureT ∞′Temperature of the fluid far away from theplateT′ Temperature of the fluid near the plateT′wTemperature of the plateκ Thermal conductivity of the fluidGrThermal Grashof numbert′ Timeu′ Velocity of the fluid in the x′ -directionv′ Velocity of the fluid in the y′ -directionu Velocity of the plategK0Acceleration due to gravitypermeability parameter2010/Fascicule 2/April­June /Tome III 95