Experimental studies on cavity flows

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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