LES Study on Mechanism of Vortex Rings behind Supersonic MVG with Turbulent Inflow

Abstract

In this study, we investigate the interaction between vortex rings behind MVG and the oblique shocks in the MVG controlled ramp flow at M=2.5 and Re θ =5760. Implicit large eddy simulation (ILES) method is used by solving the unfiltered form of the Navier-Stokes equations with the 5th order Bandwidth-optimized WENO scheme. The fully developed inflow is given by a series of turbulent profiles obtained from previous DNS simulation. It shows that the ring structure does not break down and keeps its topology after penetrating the strong shock wave and the oblique shocks is influenced a lot by the induced flow field from rings. The bump of the 3D shock wave surface is discovered and its mechanism is explained. Nomenclature

Numerical and Experimental Investigations of the Supersonic Microramp Wake

“…Different from the streamwise vortices, the so-called "vortex rings" are active across the wake shear layer. The formation of these vortices is justified as the result of the Kelvin-Helmholtz (K-H) instability acting on the wake boundary [10][11][12]. Such flow instability was afterwards also confirmed by the experiments of Lu et al [13][14] where intermittent vortical structures were evidently rolled up in the flow visualization.…”

“…The techniques used for the present simulation, including the numerical algorithm, the treatment of boundary conditions have been carefully documented in previous works [10][11][12] and is only described briefly…”

LES investigation into the generation of momentum deficits in the supersonic wake of a micro-ramp

“…Although the effects have been demonstrated through the foregoing studies, the flow physics of the microramp has not been fully understood due to the complex geometry of current device. Abundant efforts have been recently devoted to investigate the flow properties through both numerical [9][10][11][12] and experimental [13][14] methods. The major features including the momentum deficit and the primary vortex pair were originally visualized by Holden and Babinsky through wind tunnel experiments [5] .…”