Control of boundary layer streaks induced by free-stream turbulence using a novel velocity-pressure control framework.

在这个建议中，我们的目标是开发一个新的框架来主动控制空间发展的流动，并将其应用于稳定在高度自由流湍流存在的不可压缩和可压缩边界层中发展的条纹结构。这种流动场景在飞机机翼和涡轮叶片上非常常见。据我们所知，这是第一次在全球范围内尝试对此类流动进行积极控制。目前的方法是基于壁法向速度和涡量公式来推导适合控制器设计的状态空间系统，这种方法有一些局限性。新的控制框架将使用原始变量，速度和压力。这个公式提供了更大的灵活性，最重要的是，使自由流湍流的影响合并直接。然而，这种变量的选择从控制的角度带来了新的挑战，因为标准的最优控制算法不能应用。在所附的支持案例中，解释了当前方法的局限性，强调了新配方的好处，并分析了为成功控制条纹而必须处理的挑战。这项工作提供了一个独特的机会，使英国在新的和快速发展的主动流量控制领域处于领先地位。

In this proposal we aim to develop a new framework for active control of spatially developing flows and apply it to stabilise the streaky structures developing in incompressible and compressible boundary layers in the presence of high free-stream turbulence. This flow scenario is very common over aircraft wings and turbine blades. To the best of our knowledge, this is the first time that active control of such flows is attempted worldwide. The current approach, which is based on the wall-normal velocity and vorticity formulation to derive a state-space system suitable for controller design, has several limitations. The new control framework will use instead the primitive variables, velocity and pressure. This formulation offers greater flexibility and, most importantly, makes the incorporation of the effect of free-stream turbulence straightforward. This choice of variables however introduces new challenges from the control perspective because the standard optimal control algorithms can not be applied. In the attached case of support, the limitations of the current approach are explained, the benefits of the new formulation are highlighted and the challenges that must be dealt with for the successful control of streaks are analysed. This work offers a unique opportunity to put the UK in a leading position in the new and rapidly developing area of active flow control.