2020/06/05 by Stefan Schoder, Schoder, Stefan, Ivan Lazarov +3
Engineering · #Aerodynamics and Acoustics in Jet Flows #Acoustic Wave Phenomena Research #Aerodynamics and Fluid Dynamics Research
paper · pdf · doi:10.48550/arxiv.2006.03279
In modern transport systems, passengers' comfort is greatly influenced by\nflow-induced noise. In this study we investigate a generic deep cavity with an\noverhanging lip, mimicking a door gap in a vehicle, that is overflowed by air\nat two different free stream velocities, 26.8m/s and 50m/s. The turbulent\nboundary layer and the acoustic waves interact with the cavity's geometry and\nform a strong feedback mechanism. In the present work, we focus on the details\nof the compressible turbulent flow structures and their variations concerning\nthe velocity, the boundary layer as well as the domain dimensionality for a\nlater acoustic simulation within a hybrid aeroacoustic workflow. Furthermore,\nwe verify the feasibility of reducing the acoustic computational domain from 3D\nto 2D for this application by conducting a coherence study of acoustically\nactive flow structures in the spanwise direction. The role of the\nthree-dimensional Taylor-G "ortler vortices from the recirculation regarding\nthe vortex formation and the vortex-edge interaction was also evaluated.\nRemarkably for the lower approaching velocity (26.8m/s), we found a special\nvortex-edge interaction, namely an alternating sequence of complete clipping\nand a subsequent partial escape. Lastly, we assigned previous unknown peaks in\nthe pressure spectrum to their corresponding mechanisms.\n