Control of a swept-wing boundary layer perturbed by free-stre am turbulence

壁面吸力已被广泛用于减少层流边界层扰动的发展，如Tollmien-Schlichting波、横流涡旋，以及最近的Klebanoff模，即由自由流涡扰动产生的非定常流向拉长的低频扰动。壁面吸力导致了向湍流过渡的延迟，其主要优点是减少了粘性阻力、噪声和燃油消耗。本工作的中心目的是应用壁面吸力来减弱由于自由流湍流引起的后掠翼层流边界层中Klebanoff模的强度。这些流动结构在大型气动物体上从未被研究过，尽管它们在许多工业和技术应用中具有巨大的重要性，例如飞机机翼和涡轮叶片的设计。对于这些与技术相关的流动，尚未研究壁面吸力的影响。缺乏研究工作的一个原因是预测和控制这类流动极其困难。这个问题将通过数学和数值技术相结合来解决。拟议的方法将提供一个快速和数值稳健的工具包，与流体力学界以有效方式控制过渡前流动的长期努力保持一致。

Wall suction has been used extensively to reduce the growth of laminar boundary layer disturbances, such as Tollmien-Schlichting waves, cross-flow vortices and, more recently, Klebanoff modes, namely unsteady streamwise-elongated low-frequency disturbances generated by free-stream vortical perturbations. Wall suction has resulted in a delay of transition to turbulence with major benefits, such as reduction of viscous drag, noise, and fuel consumption.The central aim of the proposed work is to apply wall suction to attenuate the intensity of Klebanoff modes arising in swept-wing laminar boundary layers due to free-stream turbulence. These flow structures have never been studied over large scale aerodynamic bodies, despite their vast importance in numerous industrial and technological applications, such as the design of aircraft wings and turbine blades. The effects of wall suction have not been investigated for these technologically relevant flows. A reason for the dearth of works is the extreme difficulty in predicting and controlling such flows.The problem will be tackled by a combination of mathematical and numerical techniques. The proposed approach will offer a fast and numerically robust toolkit in line with the long-standing effort of the fluid mechanics community to control pre-transitional flows in an efficient manner.