Hybrid aeroacoustic simulation using conservation element and solution element method

Abstract

In this thesis, a new aeroacoustic solver CE/SE-APE, combining the benefit of both the acoustic perturbation equations (APE) and the conservation element and solution element (CE/SE) method, is developed for two dimensional and axisymmetric calculation. This solver targets especially for time dependent low Mach number aeroacoustic calculation as a part of the hybrid computational aeroacoustic technique which makes a demanding computational task feasible, without compromising the accuracy on physical dynamics. Throughout the chapters, the features and numerical implementation of APE and CE/SE method are introduced and discussed. Then the implementation of time-domain impedance boundary is discussed to introduce the capability on estimating the acoustic attenuation of acoustic liner, which makes the solver more capable on aeroacoustic design performance estimation. Different calculations with increasing complexity are presented in the remaining document. The accuracy of the solver on propagation in open area and in confinement is validated. The accuracy of flow induced acoustic generation by the aerodynamic source term is validated by the calculation of a benchmark spinning vortex acoustic generation using analytical source term. The aeroacoustics of flow pass square cylinder is also compared with direct aeroacoustic simulation result. With such, the applications of CE/SE-APE is further extended to the prediction of acoustic data foundation for indoor beamformer design and reduction of micropressure pulse generated by train entering tunnel.