Progress Towards Large-Eddy Simulations for Prediction of Realistic Nozzle Systems

This paper reviews the current state of large-eddy simulation (LES) for nozzle flows and discusses the issues which currently limit its application to simulating realistic noise reducing nozzle systems. LES has been used extensively to compute the flowfield of tur-bulent jets. It has shown the potential to significantly impact the design and analysis of future noise suppressing nozzle systems through improved accuracy and physical insight. There are many issues that must be resolved before an accurate prediction can be made for a complex nozzle system. Foremost, the high-order schemes used in LES must be adapted to be used in flexible gridding systems which can handle complex geometries. Hybrid Reynolds Averaged Navier-Stokes/LES schemes with appropriate interfaces must be developed to model the region near the nozzle exit and initial shear layer. Also, im-proved accuracy without reliance on empirical adjustments of simulation parameters must be demonstrated. I