Axisymmetric stagnation-point flow on a spiraling disk

Two axisymmetric stagnation-point flows impinging normal to a rotating, radially stretching disk are studied. One is the classic Homann stagnation flow and the other is the rotational Argawal stagnation flow. The combined effects of uniform rotation and linear radial stretching give a disk surface velocity in the form of a logarithmic spiral. A similarity reduction of the Navier-Stokes equations for each problem yields different coupled pairs of ordinary differential equations which are solved by a shooting technique. Parametric results for the magnitude sigma and angle phi(sigma) of the wall shear stress are computed for selected values of spiral angle phi and disk speed parameter V for both stagnation flows. Leading order large-V asymptotic results for the shear stress parameters, found to be the same for both flows, are determined and sample similarity profiles are presented. (C) 2014 AIP Publishing LLC.