Experimental Study Shows Mean Flow Skew Reduces Turbulent Mixing Layer Intensity but Preserves Core Dynamics
Researchers conducted experiments on three-dimensional turbulent mixing layers where incoming streams are skewed rather than parallel, using turning vanes and cross-wire anemometry to measure the effects. Mean and turbulent flow quantities decreased by approximately 40% in skewed configurations compared to planar ones, yet fundamental mixing layer characteristics remained largely unchanged. The findings provide an experimental framework for understanding three-dimensional free-shear turbulence, which is more representative of practical engineering applications than the traditionally studied two-dimensional case.
This experimental study investigates how mean flow skew—the angular deflection of incoming parallel streams—affects turbulent mixing layer behavior. The researchers introduced skew using turning vanes on a splitter plate and measured downstream flow evolution with cross-wire anemometry. While skewed mixing layers showed systematic reductions of approximately 40% in both mean and turbulent quantities compared to planar configurations, key structural properties persisted: mean-velocity profiles collapsed under similarity scaling, shear-layer thicknesses maintained approximately linear growth, and Reynolds-stress profiles retained their characteristic near-Gaussian form. Notably, Townsend's structure parameter—which measures turbulent momentum transport efficiency—remained approximately invariant between configurations, contrasting with skewed boundary layers where comparable skewing reduces this parameter by 30%. The study establishes controlled experimental methodology and empirical benchmarks for future investigations of three-dimensional free-shear turbulence.
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- arXiv physicsCenter
Effects of mean flow skew on turbulent shear layers. Part II. Experimental investigation
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