Fundamental Areas / Numerical Analysis of Partial Differential Equations
Convective acoustics is the study of the propagation of noise in a moving fluid as, for instance, that in a car exhaust system. The moving flow can be modeled by the Galbrun equation. The figure on the left shows the sound pressure for an acoustic eigenmode of a Mach=0.1 flow in an annular domain with absorbing outer boundary, computed with quadratic Taylor-Hood triangular finite elements. Although this formulation is not free from spurious results (like, for instance, that shown in the figure on the right), it is shown that physical and spurious modes are well separated for low Mach numbers. Further details are available in:
Dietzsch, F., Hervella-Nieto, L., Marburg, S., Rodríguez, R. and Weisbecker, H.: Physical and spurious modes in mixed finite element formulation for the Galbrun equation. Acta Acustica united with Acustica, 100 (2014) 493-512.