湍流度和粗糙度对边界层转捩影响的研究

A STUDY OF THE EFFECTS OF TURBULENCE AND ROUGHNESS ON BOUNDARY LAYER TRANSITION

工程上计算边界层转捩位置,常用以线性稳定性理论为基础的e^N方法。实际上,层流边界层转捩受坏境因素(如湍流度T,粗糙度k和压力梯度等)影响较大。所以作为e^N方法的补充,须寻求一种能同时计算坏境因素影响的方法。现只有湍流模型方法能满足这种要求。

A second-order-closure turbulence model method is used to calculate the influence of turbulence and roughness on boundary layer transition, and an experimental test is provided. The calculating results of influence of turbulence and roughness on boundary layer transition position are consistent with the experimental data of the present paper and of others. The turbulent energy distribution in the process of transition from laminar to turbulent flow has been calculated, its change shows that the laminar breakdown should occur at y/δ = 0.5, which agree with the Van Driest's result,i. e. the initial laminar breakdown should occur at y/δ=0.57 obtained by the vorticity Reynold's number approach.