Validation and Verification of a Numerical Prediction Method for Lift-off Acoustics of Launch Vehicles

Abstract

To predict harmful acoustic loading due to the intense acoustic waves generated by exhaust jets from propulsion systems of launch vehicles during lift-off, a numerical method based on computational fluid dynamics is developed. High-fidelity large-eddy simulations, or hybrid large-eddy and Reynolds-averaged Navier-Stokes simulations are employed for the computation of the hydrodynamic field. Computational aeroacoustic simulations based on full-Euler equations are applied to compute acoustic propagation to the farfield. Validation and verification studies are conducted using experimental results of free and impinging jets from a 2.4%-scale solid motor. It is found that the prediction accuracy with approximately 4 dB in overall sound-pressure level is obtained for both the free and impinging jets.

Coupled CFD-CAA Simulation of the Noise Generated by a Hot Supersonic Jet Impinging on a Flat Plate with Exhaust Hole

“…Furthermore, acoustics levels at liftoff are high, over 150 dB, and non-linear propagation effects are expected to occur [3]. Thus, linear methods become irrelevant for such situations and the use of non-linear high-order solver is recommended [4].…”

“…Scientific Advisor, Multi-physics for Energetics Department 3. Research Scientist, Multi-physics for Energetics Department 4. Research Scientist, Technical division, Launchers directorate.…”