jet noise

mixing enhancement

normal shock

jets

synthetic jet

mach number

shear layer

Aerospace science and technology

An experimental investigation of sonic transverse jets in Mach 5 cross flow over a flat plate with a sharp leading edge was carried out. Jet to free stream momentum flux ratio, J , was varied from 1.16 to 5.30. Schlieren visualisation provided information regarding mean flow features such as Mach disc height, h , separation length, x s e p as well as inherent unsteadiness. Steady wall pressure measurements diagnosed the interaction region between the jet and the incoming cross flow developing on the flat plate. To assess the jet penetration characteristics and trajectories, two-component Particle Image Velocimetry (PIV) measurements were carried out at the centreplane of the flat plate. Raw PIV image analysis was used to specify jet penetration boundaries. Ensemble-averaged streamwise and transverse velocity contours revealed the mean flow structures. The barrel shocks and the Mach disc forming the jet boundary can be easily seen and were visualised/quantified using PIV measurement technique. Maximum turbulence occurred above the Mach disc due to the presence of the shear layer and at the intersection of the windward side of the barrel shock and bow shock.

Experimental investigation of sonic transverse jets in Mach 5 crossflow