Vorticity Interaction at an Axisymmetric Stagnation Point in a Viscous Incompressible Fluid

This term is positive and is found to be surprisingly large as compared to the other effects of the same order mentioned before. The authors were informed after submitting this note that the same effect was discussed by N. H. Kemp, whose note follows below. The difference in the two treatments is that while here a perturbation (fiv) was calculated to the stagnation-point flow, Kemp solves the nonlinear equation for /0 with properly modified boundary conditions. The slope of the shear curve (at zero vorticity) as calculated by Kemp agrees perfectly with the value deduced from Eq. (10). An investigation which implicitly contains the results of the present note was made by Oguchi. He solves the equation for /o between the body and the shock, so that he obtains in one step both the shock stand-off distance and the flow in the viscous region. Properly interpreted, his solutions agree with the present results. However, Oguchi's results do not contain any curvature effects, which were found to be of the same order as the vorticity effect. The advantage of the present approach is that all four "low Reynolds Number effects" can be compared on an equal footing.