P. D. WEIDMAN AND S. MAHALINGAM

The viscous fluid motion generated by axisymmetric stagnation--point flow of strain rate impinging on a flat plate oscillating in its own plane with velocity amplitude and frequency , including uniform suction of strength is considered. A coordinate decomposition transforms the full Navier­ Stokes equations into a primary equation describing the steady flow and a secondary equation describing the unsteady motion coupled to the primary solution. The solution to the boundary--value problem is governed by two dimensionless groups: the suction parameter and the frequency parameter , where is the kinematic viscosity. Numerical integrations performed using a Runge-Kutta routine provide an exact solution to the Navier-Stokes equations. Values of the steady shear stress are found to agree with asymptotic results for large values of , with representing suction and representing blowing. The magnitude and phase of the unsteady shear stress are given over a range of frequencies sufficient to recover analytical asymptotic results at large values of . The unsteady shear stress lags the wall motion by radians for and by radians when . Velocity profiles at selected parameter values during a period of plate oscillation are presented and discussed.