Single-Point Statistics (Second Moments and Dilatation) of a Turbulent Jet Flow

The jet flow from a multi-aperture single expansion ramp nozzle produces a time-evolving flow with a Reynold's number R = 2.76e6. The flow is formed by a core stream of Mach 1.6 and a secondary stream of Mach 1.0 which combine behind a 'wavy' splitter plate. By collecting time-independent snapshots via particle imaging velocimetry data (PIV), a statistically steady flow field representation is obtained. To better understand the behavior of this jet flow, there is a need to use single-point statistics, second moments, and dilatation to characterize the flow and compare it to the behavior of a nominal splitter plate. In this study, instantaneous velocity data is used to produce root mean squared (RMS) and turbulent kinetic energy (TKE) data from fluctuating velocity data via Reynold's decomposition. Further, dilatation and Reynold's stress tensor components are obtained to better quantify the behavior or the jet flow. It will be shown from this study that there is noteworthy activity in our bottom shear layer and subtle differences in the shock train compared to the baseline case.