A numerical study of strained three-dimensional wall-bounded turbulence

摘要: Channel flow, initially fully developed and two-dimensional, is subjected to mean strains that emulate the effect of rapid changes streamwise spanwise pressure gradients in three-dimensional boundary layers, ducts, or diffusers. As previous studies homogeneous turbulence, this done by deforming domain a direct numerical simulation (DNS); here however periodic only two directions contains parallel walls. The velocity difference between inner outer layers controlled accelerating channel walls their own plane, as earlier flows. By simultaneously moving straining we duplicate both regions spatially developing case. results are used address basic physics modelling issues. Flows subject impulsive three-dimensionality with without deceleration an adverse gradient (APG) considered: imitating swept-wing pure skewing (sideways turning) imposed. APG influences structure measured for example ratio shear stress kinetic energy, much more than does skewing. For deformations, evolution Reynolds profoundly affected velocity–pressure-gradient correlation [Pi]ij. This term – which represents finite time required strain modify shape orientation turbulent motions primarily responsible (lag) direction stresses, well-known feature perturbed layers. Files containing DNS database model-testing software available from authors distribution, tools future closure-model testing.