CFD Analysis of Separated Flow over the Gaussian Bump using Various Turbulence Models

Smooth body separation remains a challenging problem in understanding the aerodynamic behavior of various aerospace vehicles, significantly impacting their operational performance. The focus of this paper is on the numerical simulation of the flow field of a Gaussian bump (also known as the Boeing bump), which represents a model benchmark three-dimensional geometry involving the smooth body separation. The available experimental data with detailed pressure variations along the streamwise centerline and ridge of the bump provides a robust basis for testing the accuracy of various turbulence models in conjunction with the Reynolds-Averaged Navier-Stokes (RANS) equations in predicting the separation and reattachment behind the bump in the downstream region. There have been previous computational efforts employing the Spalart-Allmaras (SA) model; however, the discrepancies between the computations and experimental data remain. This paper investigates the application of the one-equation Wray-Agarwal (WA) turbulence model and compares its performance with the SA model predicting the separated flow over the bump. The results include the pressure coefficients along the centerline and the ridge, providing a comprehensive evaluation of the performance of the WA model. All the results were obtained employing Ansys Fluent with the implementation of the WA model through a user-defined function (UDF).