RANS-CFD Based Assessment of Corrections Applied to the Measured Characteristics of Supersonic Configurations in a Low Speed Wind Tunnel

Abstract

The CFD software package Star-CCM+ was used to investigate the effects of the model support system and test section walls on a double-delta wing, representative of long-range supersonic configurations, in the University of Washington's Kirsten Wind Tunnel in an effort to improve current wind tunnel test corrections. The Star-CCM+ simulation-derived support corrections were validated using past wind tunnel models and support corrections.Simulations indicated that the interference effects due to the model support system are non-negligible and must be accounted for. New model support corrections were computed using CFD and wind tunnel data. Wall effects corrections were also evaluated via RANS CFD and results compared well to classical corrections traditionally applied by the Kirsten Wind Tunnel. The pitching moment curve slope was underpredicted, however, with CFD simulations. Engine nacelle form factors were also calculated with Star-CCM+ to add new nacelle internal duct drag corrections to wind tunnel data. All CFD derived corrections were applied to past uncorrected wind tunnel data, compared to data with KWT's standard corrections, and to Star-CCM+ simulations of the models in freestream conditions. The CFD derived corrections appear to improve the resulting "free flight" wind tunnel data for the wing alone case. More work is necessary, however, for full configurations and CFD-based corrections should be validated with follow-on dedicated "Tare and Interference" (T\&I) testing.