Advanced CFD Methods for Hypervelocity Wind Tunnels.

摘要

There are two main components of the work performed during this project. First, a finite-rate vibrational energy relaxation model was developed to study how the possible presence of water vapor in the Tunnel 9 facility could affect the flow properties. We find that water vapor levels at about 500 parts per million (ppm) could cause appreciable relaxation of the nitrogen test gas, however, even at these large levels, the effect on the flow quality is minimal. Secondly, a novel grid generation scheme for hypersonic nozzle flows is presented. The grid is based on the characteristic lines of the supersonic regions of the flow. This allows for grid alignment and clustering along shock waves present in the flow. Results from simulations run on the AEDC Hypervelocity Tunnel 9 Mach 14 nozzle give good agreement with simulations performed using a conventional grid. Some results from an investigation into the effect of wall contour discontinuities present in the Mach 14 Nozzle are presented. Avenues for future research into flow irregularities in the Mach 14 nozzle are outlined.