Statistical Analysis of CFD Results for Missile Surface Pressures

Abstract : An international computational aerodynamics study under the auspices of The Technical Cooperation Program (TTCP) Weapons Technology Panel 2 (APN-TP-2) involving participants from defense research laboratories of the United States, United Kingdom, Canada, and Australia was recently completed. The purpose of this study was to examine computational predictive technologies for finned missile shapes by comparing Navier-Stokes predictions to experimental data. Experimental data consisting of surface pressures on the body and fins, flow field pitot pressures, and force measurements were available for comparison to the computational results. The computational results for this study established an extensive database for evaluation and comparison. The fall database consists of results from six Navier-Stokes codes obtained by seven multi-block patched and unstructured grids for five distinct test cases. The statistical analysis techniques developed to help provide an evaluation of the predictive techniques are described. Quantitative results of the analysis of the differences between computational and experimental results are presented graphically and quantitatively in terms of medians, standard deviation, and a figure of merit to assist in the overall evaluation of the study results. The good performance achieved using the Spalart-Allmaras turbulence model and multi-block patched and unstructured grid techniques are noted in the findings.