Colloquia

Summary

This thesis investigated noise generation mechanisms by turbulent boundary layers, particularly trailing-edge noise. This mechanism is significant in various engineering applications such as wind turbine and aircraft. Amiet’s trailing-edge noise model serves as the foundation of this study. It’s semi-empirical parameters, often based on a single flat plate assumptions, struggle with real-world applications where the turbulent boundary layer experiences local disturbances and non-equilibrium effects. This study aims to understand how local disturbances to the turbulent boundary layer impact noise generation. This is done by investigating the effect of imposing a local pressure gradient on the characteristics of the turbulent boundary layer, critical to Amiet’s trailing-edge noise model.

Using both Computational Fluid Dynamics (CFD) simulations and wind tunnel validations, the study examines a flat plate setup with strategically placed counter bodies to induce a local pressure gradient. The results show that the counter body height and angle of attack affect boundary layer properties and trailing-edge noise levels, as observed in the experiments. This work primarily established and validates a framework enabling further studies on non-equilibrium effects on boundary layer conditions and trailing-edge noise, ultimately advancing semi-empirical noise prediction models for practical applications.