Spectral model of wall-pressure fluctuations applied to the transonic flow around a generic space launcher

Abstract

High fidelity approaches based on LES or hybrid RANS-LES methods allow to predict unsteady quantities such as wall-pressure fluctuations for complex configurations. However, they are still expensive and time-consuming in terms of computational resources, especially in the earlier phases of design. In this context, this study presents an analytical spectral model for predicting wall-pressure fluctuations for complex, three-dimensional configurations using mean flow data as input. The model is first assessed on a transonic launcher configuration simulated with Zonal Detached Eddy Simulation (ZDES). Then, model outputs, namely the fluctuating wall-pressure coefficient and one-point pressure spectra are compared to numerical results to the reference ZDES computation and available experimental data. Finally, the present model is applied to the RANS mean flow fields using the Spalart-Allmaras model. Using inputs from RANS computations is more challenging compared to ZDES as some turbulent quantities are not provided by the simulation and must be modeled, but it represents an outstanding gain in term of the global computational cost. The predicted fluctuating wall-pressure coefficients and one-point spectra are found to be in very good agreement with ZDES data, given the computational efficiency of the model.