On the Convection Velocity of Wall-Bounded Turbulence Resolved by ZDES Mode III at $$Re_\theta = 13 000$$ R e θ = 13000

Abstract

WMLES simulations of a flat-plate zero-pressure-gradient boundary layer are done with the Zonal Detached Eddy Simulation Mode III technique over a wide range of Reynolds numbers 3 150 ≤ Re θ ≤ 14 000. A WMLES field is compared with the WRLES interpolated onto the WMLES mesh. Two interface heights are considered, y interface = 0.1δ and y + interface = 3.9 √ Re τ. The prediction and resolved fraction of mean skin friction is discussed, as well as remaining issues, especially in the logarithmic layer. An excess of high-wavelength streamwise velocity fluctuations is observed below the RANS/LES interface with y + interface = 3.9 √ Re τ , and studied by a spectral convection velocity analysis, leading to the suggestion that it may be a footprint of coherent structures located further away from the wall.

Advanced simulations of turbulent boundary layers under pressure-gradient conditions

“…26 and 27 respectively. Several similarities to spectral analysis of zero pressure gradient turbulent boundary layers simulated with the ZDES mode 3 are identified 21,57 . The peak of the PSD for u 2 is located below the RANS/LES interface near of outer very large scale would also be observed near the wall for λ x from about 0.2δ to almost 10δ 43,[63][64][65] , although this does not mean that the longest structures are located that close to the wall 63,64,66 .…”

“…In the WMLES approach of the ZDES (mode 3), the separation between the RANS and the LES regions is given by an interface whose law is specified by the user. Several works have dealt with the interface positioning and the effect of different interface laws 21,40,46,48,56,57 . Very satisfactory results have been obtained in the case of a high-Reynolds-number turbulent boundary layer at zero pessure gradient in quasi-incompressible conditions 21,40,56 whole spanwise vorticity is considered instead of using the boundary layer approximation ω z ≈ −∂ u /∂ y (where ω z denotes the mean spanwise vorticity).…”