High-Fidelity Numerical Simulation of a Chevron Nozzle Jet Flow

This paper reports results from our ongoing research on the noise of jets exhausting from chevron nozzles. Results from the simulation of a moderate Reynolds number cold jet flow exhausting from a chevron nozzle designated as SMC006 are presented. This nozzle geometry was experimentally studied by the researchers at the NASA Glenn Research Center. Results from the simulation are compared with the experimental measure-ments. The SMC006 nozzle contains six symmetric chevrons that have an approximately 18-degree penetration angle. In this study, the flow inside the nozzle geometry and the free jet flow outside are computed simulta-neously by a high-order accurate, multi-block, large eddy simulation (LES) code with overset grid capability. For the SMC006 chevron nozzle test case, the governing equations are solved on approximately 400 million grid points using 2048 processors in parallel. The main emphasis of the simulation is to compute the jet flow in as much detail as possible and accurately capture the physical processes that lead to noise generation. It is especially critical to capture the enhanced shear layer mixing due to chevrons that takes place within the first few diameters downstream of the nozzle exit. The goal of the present simulation is to resolve the full noise frequency range of interest. Our calculations resolve the jet flow field in an unprecedented level of detail by utilizing extreme computational resources and and thus they are the first of their kind. Despite some issues such as an order of magnitude lower simulation Reynolds number (relative to experimental value) and un