ISDP: Inverse Shape Design Procedure

Friday, May 28, 1999 - 10:10am - 10:00am
Vincent 570
Gary Strumolo (Ford Research)
Most computational fluid dynamics (CFD) analyses today follow the direct method: specify the shape of an object and CFD will compute the velocity or pressure along its surface. This report will show how to perform the inverse operation; namely, how to specify a velocity or pressure distribution and compute the shape of a body needed to achieve this distribution. The procedure, called ISDP, is fairly robust and can obtain the desired shape even when the initial guess is far from the final one. It works by migrating a set of vortex elements, whose strengths are related to the desired distributions, until they reach spatial positions consistent with them. Often, the final shape is reached with only a few dozen iterations, each of which is computed directly without any matrix inversion. Two types of boundaries are allowed: free and fixed. Free boundaries are ones where the velocity/pressure is known but the shape isn't. Fixed boundaries are ones where the shape is prescribed but the velocity/pressure is unknown.

The method is currently limited to potential flow in two dimensions, although the procedure can be extended to three. Sample problems will illustrate its capability, accuracy, and ease of use.