Geometry and scale relationships in high Reynolds number turbulence determined from three-dimensional holographic velocimetry

Holographic particle imagevelocimetrymeasurements of a fully developed turbulent flow in a square duct ( Re H =v c H/ν=1.2×10 5 , η=100 μ m ,  Re λ =310) are used for examining the relative alignment between filtered vorticity, strain-rate and subgrid-scale stress tensors. Similar to DNS and previous measurements, the filtered vorticity has a preferred alignment with the intermediate strain-rate eigendirection. Contrary to typical eddy viscosity models, the most compressive strain-rate and most extensive subgrid-scale stress eigendirections have a strongly preferred relative orientation of 34°. The orientations of the other eigendirections are less deterministic and more complex.