Preliminary investigations on the use of spectral methods for flow calculations

Abstract

Numerical simulation of fluid flows is increasing in popularity and utility in the study of wind effects on structures. Many different schemes, such as finite difference and finite elements, have been used. For this study, sponsored by the Federal Highway Administration, many of these methods were studied and compared. A Chebyshev-collocation Spectral method was eventually chosen for its extreme computational efficiency. Spectral Methods have been used in a variety of flow calculation problems. Others have applied it to channel flows and compressible flow problems. The current work is an attempt toward applying the spectral method to flow around bluff bodies, in particular rectangular prisms and flat plates. The first test of the technique was a model of bar deflecting along it's axis due only to it's own weight. Then, a two dimensional Poisson solver was implemented with the method. Next, a uni-domain Navier-Stokes solver was attempted. Currently, a multidomain two dimensional incompressible Navier Stokes solver is under development. In addition, a microcomputer flow visualization program has been developed using a steady state finite difference flow modeler to provide sample data. Finally, some conclusions and areas of future work will be discussed.