The effect of convex wall curvature on the structure of the turbulent boundary layer

摘要

Effects of convex wall curvature on turbulent boundary layer flow are studied in this article using a numerical method. Since the non-linear k-ε model often used in engineering applications cannot satisfy the distribution and wall-limiting behaviour of the Reynolds stress components, an improved low Reynolds number k-ε turbulence model has been employed to model turbulences in this study. Based on numerical solutions, turbulent intensity, turbulent shear stress, and mean velocity are calculated. The results show that the turbulent intensities and turbulent shear stresses are decreased on convex walls compared with flat plates under similar conditions. The numerical results also show that for the boundary layer on convex surfaces, the stabilizing effects lead to less turbulent momentum exchange between fluid particles. The rate of integral parameters of the boundary layer such as momentum thickness and displacement thickness is reduced on convex curvature compared to their values on the flat plate. To validate the numerical method, the numerical results have been compared with previous measured values and good agreement has been obtained.