Scaling mean velocity and Reynolds stress of a turbulent boundary layer submitted to an adverse pressure gradient

Abstract

Despite considerable progress in understanding zero pressure gradient boundary layers, turbulence in adverse pressure gradient (APG) boundary layers remains less well understood, particularly in high Reynolds number flows. Unfavorable pressure gradient regions are commonly encountered in industrial applications, but turbulence models often lack the physical basis necessary for reliable predictions in these flows. This study focuses on analyzing the effects of adverse pressure gradient on boundary layer scaling, essential for predicting flow characteristics and validating turbulence models. Building on recent advances in experimental methods and using large-scale particle image velocimetry (PIV), the research aims to provide an analysis of turbulent boundary layer flows in APG. Experiments have been carried out in a wind tunnel using inclined plates to induce pressure gradients at an angle of $-8^{\circ }$, complementing an existing database obtained at $-5^{\circ }$ (see Cuvier et al., 2017) and offering new insights into flow behavior. An analysis of the literature has enabled the authors to compare various scaling approaches and to propose a scaling that is suitable for both mean velocity and Reynolds stress.