Computational Prediction of Pressure Environment in the Flame Trench

摘要

A numerical investigation on the computational requirements for the simulation of jet impingement flows is presented. Comparisons between different computational fidelities (inviscid, implicit large eddy simulation and detached eddy simulation) and boundary condition treatments (slip and no-slip) are assessed for a jet impingement model problem. Spectral analysis, Proper Orthogonal Decomposition (POD), and other statistical tools are used to analyze the unsteady flow features. These tools provide detailed insight into the shock oscillations, unsteadiness of the jet, and possible coupling mechanisms. The highly unsteady shock oscillations at the primary and secondary impingement locations can be captured with only a few POD modes. A computational model able to correctly predict the key features of the unsteady pressure field at a launch site must temporally and spatially resolve these most energetic flow structures. A new jet impingement model problem is proposed that mimics the second deflection of the jet commonly observed in traditional flame deflectors configurations. A feedback phenomena which couples the jet dynamics with the unsteadiness at the primary and secondary impingement locations was identified for this configuration. Finally, the pressure environment for the Falcon Heavy launch vehicle is simulated and some of the key physical mechanisms from the model jet impingement problem are identified.