Pseudo-characteristic formulation and dynamic boundary conditions for computational aeroacoustics

Abstract

The objective of this thesis is to evaluate the possibilities offered to computational aeroacoustics (CAA) by rewriting the compressible Navier-Stokes equations using a characteristic type formulation proposed recently by Sesterhenn. A method for the direct computation of the instantaneous sensitivities of unsteady compressible flows is also proposed. It is based on complex differentiation of the full compressible Navier-Stokes equations and does not require differentiation of the stored unsteady flow solution. The method does not rely on any assumption on the base Navier-Stokes solver, and can therefore be implemented in a straightforward way. The method is assessed on several cases, including a two-dimensional subsonic mixing layer.