Evidence of shocklets in a counterflow supersonic shear layer

In this Letter, experimental evidence of shocklets in a counterflow Mach 2 shear layer is presented. Schlieren photography reveals shock waves emanating from the turbulent structure; they are normal in the vicinity of the structure and weaken into Mach waves a short distance away from the shear layer. The slope of the Mach waves suggests that the turbulent structures are nonstationary, even though the shear layer is symmetric.