Effect of buoyancy forces on certain viscous flows with suction

Summary

In the first part of the paper the effect of gravity on the unsteady flow of a viscous incompressible fluid due to the motion of an inclined infinite porous flat plate along its line of greatest slope is discussed. The boundary layer equations are integrated for two cases: (1) when the suction velocity at the plate is constant; (2) when the suction velocity at the plate is inversely proportional to the square root of time. Explicit expressions for velocity and temperature distribution are given in both the cases for any σ (Prandtl number). In the case of a uniformly accelerated plate, it is found that for σ=1 and suction velocity proportional to t ^−1/2 the velocity increases with the non-dimensional parameter βg sin α. (T _w−T _∞)/D and the skin friction at the plate is proportional to the square root of time. In the second part of the paper it is found that in the case of the free convection flow of a compressible fluid past an infinite flat plate subjected to suction the skin friction at the plate increases with gravity and decreases with suction.