Receptivity of the transonic boundary layer to acoustic noise

当前客机设计的一个主要重点是延迟飞机机翼边界层的层流-湍流过渡。已经确定，噪声、自由流湍流和壁面粗糙度是层流-湍流过渡的原因，层流-湍流过渡始于边界层对外部扰动的接受能力。本项目将重点研究跨音速状态下的可接受性。本文将研究托尔曼-施里希汀波和横流涡的产生。为此，假设雷诺数较大，将构造Navier-Stokes方程的渐近解。在此基础上，提出了通过抑制可接受性过程来控制层流-湍流过渡的方法。

Currently a major priority in passenger aircraft design is to delay laminar-turbulent transition in the boundary layer on aircraft wings. It has been identified that acoustic noise, free-stream turbulence and wall roughness are responsible for the laminar-turbulent transition which starts with the receptivity of the boundary layer to external perturbations. This project will focus on the receptivity in transonic speed regimes. Both the generation of the Tollmien-Schlichting waves and of the Cross-Flow vortices will be studied. For this purpose the asymptotic solutions of the Navier-Stokes equations will be constructed assuming that the Reynolds number is large. Based on these solutions the means to control the laminar-turbulent transition by suppressing the receptivity process will be developed.