The Effect of Micro-ramps on Supersonic Flow over a Forward-Facing Step

Abstract

The effect of micro-ramp control on fully developed turbulent flow over a forward-facing step (FFS) is investigated in a supersonic low-noise wind tunnel at Mach number 3 using nano-tracer planar laser scattering (NPLS) and supersonic particle image velocimetry (PIV) techniques. High spatiotemporal resolution images and the average velocity profiles of supersonic flow over the FFS with and without the control of the micro-ramps are captured. The fine structures of both cases, including the coherent structures of fully developed boundary layer and the large-scale hairpin-like vortices originated from the micro-ramps as well as the interaction of shock waves with the large-scale structures, are revealed and compared. Based on the time-correlation images, the temporal and spatial evolutionary characteristics of the coherent structures are investigated. It is beneficial to understand the dynamic mechanisms of the separated flow and the control mechanisms of the micro-ramps. The size of the separation region is determined by the NPLS and PIV. The results indicate that the control of the micro-ramps is capable of delaying the separation and diminishing the extent of recirculation zone.

Relation Between Geometry and Wake Characteristics of a Supersonic Microramp

“…Various past studies have assessed the effectiveness of micro ramps for flow control [1,2,6,[9][10][11][12][13][14]. The flow structure of the micro ramp wake has been explored in detail both computationally and experimentally [5,15,24,[16][17][18][19][20][21][22][23].…”

Aerodynamic measurement of a large aircraft model in hypersonic flow

“…The shock tunnel is an important piece of ground equipment in the aerospace research field. The current tunnel limits the size of the aircraft model, [2,3] but can be used to provide a high total pressure and a high total temperature at relatively low cost. The traditional shock tunnel is only capable of satisfying the measurement of models several hundred millimeters in length, which renders experiments on full-scale models impossible.…”

Experimental studies on flow visualization and velocity field of compression ramp with different incoming boundary layers

“…Its spatial resolution achieves micrometer scale, with a time resolution of 6 ns, the temporal correlation resolution reaches 0.2 µs. In some previous experiments [13][14][15][16][17][18] NPLS technique has been applied very well.…”