In the road of assessing the validity of logarithmic law in wake flows: A review

Abstract

In any application of wall-bounded or shear fluid flows, near-wall boundary layer and shear layer are the places of struggle between viscous and inertial forces. After development and spread of using wall functions for modeling near-wall region of boundary layer in wall-bounded turbulent flows, the importance of accurate prediction and modeling of different layers of boundary layer, particularly the so-called logarithmic layer becomes more crucial in aerodynamics. Due to the intrinsic characteristics of flow structure in log-layer and wide-spread applications of wake flows, the presence of these characteristics in wake flows rather than wall-bounded flows opens a new window to the researchers to investigate the possibility of using log-law within wake regions, particularly on wake centerline for modeling purposes. On the applications of wake modeling and studying, we can point out to wing and blade trailing edge design, exhaust flow of pipes and ducts (e.g. nozzle exhaust or internal flow of polymers in dimpled pipes), and vortex generator design which are just a few examples of the areas with great interest in both fundamental scientific research, that is, developing optimum and accurate Computational Fluid Dynamics (CFD) tools and their industrial applications. In this article, a brief description about different approaches, previous efforts and case studies, and similar analogous problems is presented to give a better perception to the future researchers. Key words: Logarithmic law, turbulent boundary layer, wake centerline, vortical structure.