Accession Number:

ADA222704

Title:

Particle Simulation of Hypersonic Flow

Descriptive Note:

Final rept. 1 Apr 1988-31 Mar 1990

Corporate Author:

STANFORD UNIV CA DEPT OF AERONAUTICS AND ASTRONAUTICS

Personal Author(s):

Report Date:

1990-04-24

Pagination or Media Count:

75.0

Abstract:

A limitation of the DSMC method is that it does not allow efficient use of vector architectures that are predominate in current supercomputers. A new selection rule for collisions between simulated molecules is developed which is highly compatible with vectorization. The collision-selection rule is shown to give identical results to the DSMC method in predicting shock-wave structure and in predicting the correct mean-free path variation with density and temperature for power-law interactions ranging from hard sphere to Maxwell molecule. Algorithmic improvements beyond those related to vectorization issues alone are also introduced, making possible simulations of single-species, rarefied, 3D hypersonic flows employing 10 million particles and 0.5 million cells. The performance of the algorithm on the Cray-2 ranges from 1 to 2 microsecondsparticletime-step. Roughly 500 to 1000 time-steps are needed to time average the results of a simulation, leading to run times of 2 to 5 hours on the Cray-2 for large problems. Keywords Particle method Rarefied flow Direct simulation Monte Carlo Collision selection.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE