Shoch-driven gas curtain: fractal dimension evolution in transition to turbulence

摘要

We present estimates of the Hausdorff fractal dimension of a planar section of the interfaces on the sides of a thin curtain of heavy gas (SF_6) embedded in air and accelerated with a planar shock wave at Mach 1.2. As the Richtmyer-Meshkov instability develops, eventually leading to a transition to turbulence in the curtain, the fractal dimension of the interfaces increases from an initial value not exceeding 1.10 to a maximum value 1.36+-0.07. This value is close to that experimentally measured for fully developed turbulence. The growth of the fractal dimension is closely related to mixing in the flow. It represents an important and previously unmeasured property in the transition to turbulence due to Richtmyer-Meshkov instability.