Coupled Overset Unstructured Discontinuous Galerkin Method for Launch Environment Acoustics Prediction

Harris, R., Collins, E. M., Luke, E., & Sescu, A. (2016). Coupled Overset Unstructured Discontinuous Galerkin Method for Launch Environment Acoustics Prediction. AIAA Journal. AIAA. 54(6), 1932-1952. DOI:10.2514/1.J054563.

Abstract

A novel approach for the accurate prediction of launch environment acoustic physics is presented. Launch vehicles experience extreme acoustic loads during liftoff, driven by the interaction of rocket plumes and plume-generated acoustic waves with ground structures. In this work, a well-established hybrid Reynolds-averaged Navier–Stokes/large-eddy simulation unstructured mesh solver is used to efficiently model the complex turbulent plume physics, and a high-order accurate discontinuous Galerkin solver is used to accurately propagate acoustic waves across large distances throughout the launch environment. The two solvers operate on separate overlapping meshes, and an innovative overset coupling approach is used to transmit the plume-generated acoustics to the far field in a one-way manner in which the turbulent plume prediction is unaffected by the outer acoustic propagation physics. The framework upon which the solvers are developed is described along with details outlining the overset domain connectivity and interpolation methods. Results are presented that demonstrate the accuracy of the capability for aeroacoustic predictions, and the merits of the approach are evaluated using a notional space launch system launch environment in which rocket plumes are represented by transient acoustic sources.