BCFD Analysis for the 1st AIAA Propulsion Workshop: Nozzle Results

Abstract

Unstructured grid solutions for the first AIAA Propulsion Aerodynamics Workshop (PAW-1) are presented for the S-Duct test case. The BCFD code is applied to custom unstructured grids based on the guidance of the Propulsion Aerodynamics Workshop Committee for appropriate surface grid spacings. The focus of the work is to determine the suitability of CFD to predict the static and total pressure distribution in an offset diffuser. Wall pressures, boundary layer profiles, and average properties at the virtual aerodynamic interface plane (AIP) were collected for a range of grid resolutions, two viscous flux discretizations, and several turbulence modeling options. A grid resolution study demonstrates grid convergence of the wall pressure samples and the effect of turbulence modeling choices are studied with comparison to experimental data provided by the PAW-1 Committee. These results show that the streamline curvature correction for the SpalartAllmaras turbulence model provides superior estimates of the wall-pressure compared to other options. Experimental data collected on a total pressure rake located at the AIP were compared to data extracted from the CFD simulations at the total pressure probe locations. The CFD simulations are shown to provide a reasonably accurate prediction of recovery regardless of turbulence model; however, less accuracy was obtained in the measure of distortion. This may be a result of not including the total pressure rake in the CFD model.