Flow past impulsively started bodies using green's functions

Abstract Numerical solutions are obtained for viscous incompressible flow over an impulsively started cylinder and a 2:1 ellipse at an angle of attack of 20°. The Navier-Stokes equations with vorticity and stream function as variables are solved using a cmbination of finite differences and Green's function. The Reynolds numbers are 500 and 200 for the cylinder and ellipse respectively, and computations are continued up to a dimensionless time of 1.5. For the flow over an ellipse the lift force as well as the drag are initially very large and then rapidly decay. The rear stagnation point gradually moves down and separation occurs at t ∼ 1.1. Recent experimental studies by Taneda for flow at the same geometry indeed show large values of lift following the initial motion and gradual downward movement of the rear stagnation point.