Experimental studies on cavity flows

不同来源的扰动和畸变对湍流边界层的发展有显著影响，并改变了湍流边界层的特征。这会导致升力损失、阻力增加和噪音水平升高。这种扰动/畸变边界层存在于各种工程应用和自然环境中。随着我们努力实现NetZero，开发新的理解以及与实际应用相关的预测模型变得越来越重要，其中边界层受到外部源的扭曲/干扰。在这个实验项目中，我们的目的是探索不同类型的空腔对湍流边界层流动的影响。空腔会对流动产生时空扰动，这取决于流动的形式。首先，我们将重点研究正交深空腔对湍流边界层发展的影响。这将随后添加进一步的几何变化的空腔，以检查所经历的边界层的扭曲。我们将进行一系列的测量，包括壁压测量和三维粒子图像测速（PIV）。实验将在新折射率匹配设备中进行，该设备目前正在该大学委托使用。这一设施允许访问以前不可能获得的数据和信息。结果数据将使用先进的数据分析工具进行分析，以了解造成阻力和噪音的流动特征。高保真数据还将与开源CFD软件一起使用，以确定无法通过实验获得的流量。总的来说，这个项目将使我们了解外部施加的扭曲对湍流边界层发展的影响

Perturbation and distortion from different sources influence the development of turbulent boundary layers significantly and alter their characteristics. This results in loss of lift, increased drag and higher noise levels. Such perturbed/distorted boundary layers are present in various engineering applications and natural environment. As we strive towards achieving NetZero, it is increasingly important to develop new understanding as well as predictive models relevant to practical applications where the boundary layers are distorted/perturbed by external sources. In this experimental project, we aim to explore the effects of different types of cavities that are flush to the wall on a turbulent boundary layer flow. The cavity will induce Spatio-temporal disturbances on the flow depending on the flow regime. Initially, we will focus on the effects of orthogonal deep cavities on the development of the turbulent boundary layer. This will be followed by adding further geometric variations to the cavities to examine the distortions experienced by the boundary layer. We will carry out a whole range of measurements including wall-pressure measurements, and three-dimensional Particle Image Velocimetry (PIV). The experiments will be carried out in the new Refractive Index Matched Facility that is currently being commissioned at the University. This facility allows access to data and information that has not been possible previously. The resulting data will be analysed using advanced data-analysis tools to understand the flow features responsible for drag and noise. The high-fidelity data will also be used together with open-source CFD software to determine flow quantities that are inaccessible with experiments. Overall, this project will allow us to understand the influence of externally imposed distortion on the development of turbulent boundary layers