Octant analysis based structural relations for three-dimensional turbulent boundary layers

Abstract

A flow structure based triple-product correlation model developed by Nagano and Tagawa [J. Fluid Mech. 215, 639 (1990)] has been expanded to three-dimensional turbulent flows. Three-dimensional turbulent boundary layer data obtained away from the vortex in a wing-body junction flow are analyzed to calculate the contributions from eight velocity octants to the stresses and higher-order products. The analysis showed that the sweep and ejection modes dominate the flow physics of some shear stresses and some triple products, while the interaction modes are negligible away from the wall. These experimental observations are used together with the extended Nagano-Tagawa mathematical model to obtain relations among the triple products in three-dimensional turbulent boundary layers that can simplify the turbulent diffusion modeling used in Reynolds-averaged Navier-Stokes equations. Results show that û3, û2v̂, and v̂3 triple product correlations can be modeled if an appropriate turbulence model is described for the ûv̂2 triple product correlation, and that û2ŵ v̂2 ŵ triple products correlations can be modeled if an appropriate turbulence model is described for the ûv̂ŵ triple product correlation. © 2006 American Institute of Physics.