Aerospace Engineering, Sharif University of Technology
The thin-layer Navier-Stokes equations are solved for two complete missile configurations on an IBM 3090-200 vectro-facility supercomputer. The conservation form of the three-dimensional equations, written in generalized coordinates, are finite differenced and solved on a body-fitted curvilinear grid system developed in conjunction with the flowfield solver. The numerical procedure is based on an implicit approximate factorization algorithm employing a multi-grid approach in the simulation of flow about complex finned-missile configurations. The grid program is based on the method of algebraic interpolation and is capable of generating three-dimensional grid systems for missile bodies and finned-missiles having up to eight control surfaces. The multi-grid method improves the CPU time by as much as a factor of 40 over the conventional single-grid method. In addition, using the IBM's vectorizing and optimizing Fortran compiler, speeds up the total execution time (CPU) by more than 90 percent over the same code run on a non-vector architectured machine. The present method is applied to complete missile configurations in supersonic flow at high angles of attack. The predicted aerodynamic coefficients match the available wind-tunnel data with good accuracy. Flow nonlinearities such as shock and separation are detected and verified with the available experimental reports. Body vortex separation and classical patterns of vertical flow are also numerically obtained and examined for vortex interaction effects.