Direct Numerical Simulation of Turbulent Flow Past an Acoustic Cavity Resonator

The present project studies the sound pressure inside an acoustic resonant cavity driven by turbulent flow. With this numerical study as an interim result, the ultimate goal is to improve the industrial layout of resonant cavities, in general: For example to circumvent resonance conditions. The current rise of high-performance computing allows us to simulate the dynamics of the non-linear turbulence-acoustic interaction by the high-quality method of a Direct Numerical Simulation (DNS). For the first time, the three dimensional geometry investigated here can be studied numerically in full detail without simplification. So far numerical studies of Helmholtz resonators with resolved neck shape do not consider an inflowing turbulent boundary layer or do not resolve all system scales, but assume some form of turbulence model. To effectively run the DNS on a supercomputer, a multi-block parallelization method is newly implemented for complex geometries, which consist of multiple, different sized blocks. Both in strong and weak scaling test a previous single-block parallelization is outperformed. The optimal load of gridpoints per core is identified and a distinction between misleading and meaningful weak scaling tests is made.