Comparison of Numerical Flow Field Predictions for Army Airdrop Systems

Report No. ARL-TR-1983
Authors: Sahu, Jubaraj; Edge, Harris L.; Heavey, Karen R.; Stein, Keith R.; Benney, Richard J.
Date/Pages: May 1999; 31 pages
Abstract: A computational study has been performed to determine the aerodynamics of Army airdrop systems using computational fluid dynamics (CFD). The validation of flow field predictions from CFD software packages for airdrop systems is difficult because comprehensive experimentally obtained data are lacking. This is especially true for real systems because obtaining desired flow field data during a test is not practical or possible with available technologies. This report examines the results of predictions from two separate CFD codes for the same airdrop systems as an initial step toward validating high performance computing software for modeling airdrop systems. Numerical results have been obtained on two airdrop systems used by the U.S. Army: the T-10 personnel system (no payload) and the G-12 cargo system with and without a payload. The two software packages used for the comparisons are a CFD code that employs a stabilized semi-discrete finite element formulation of the incompressible Navier-Stokes equations and CFD++, a commercially available code. For this numerical experiment, computed unsteady flow fields were obtained with the same unstructured mesh, and predicted flow fields were compared. Similarities and discrepancies in the comparisons are highlighted, and conclusions are drawn from these results.
Distribution: Approved for public release
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Last Update / Reviewed: May 1, 1999