Taylor hypothesis and large-scale coherent structures

摘要: The applicability of the Taylor hypothesis to large-scale coherent structures in turbulent shear flows has been evaluated by comparing actual spatial distributions structure properties with those deduced through use hypothesis. This study carried out near field a 7[sdot ]62 cm circular air jet at Reynolds number 3[sdot ]2 x 10 4 , where and their interactions have organized controlled excitation. Actual obtained phase-average hot-wire data, measurements having repeated different points over extents crosssections fixed phase. corresponding ‘spatial’ these (by using hypothesis) from temporal data appropriate phases locations, show that works quite well for an isolated if constant convection velocity, equal centre is used everywhere across flow. popular local time-average or even instantaneous streamwise velocity produces unacceptably large distortions. When like pairing are involved, no can be found which works. Distributions terms Navier–Stokes equation contributing vorticity, but neglected hypothesis, quantitatively determined. These associated background turbulence field, not motion neglected. In particular, pressure term due cannot