Speaker: Dan Stanescu
Title: Spectral Methods in Computational Aeroacoustics.
Affiliation: Concordia University, Canada.
Date: Friday, February 418.
Place and Time: Room 101 - Love Building, 3:35-4:35 pm.
Refreshments: Room 204 - Love Building, 3:00 pm.

Abstract. Spectral methods are well known for their high accuracy and low dissipation/dispersion properties, which should make them ideal candidates for Computational Aeroacoustics (CAA). The seminar will discuss CAA applications, with particular emphasis on turbofan tone radiation, of spectral methods that are based on dividing the computational domain in non-overlapping patches and discretizing the governing equations on each of them by a stand-alone spectral collocation method. The methods can practically handle geometries of any complexity once the patches themselves are given as an unstructured, finite element type, grid. The patches are then assembled together by imposing continuity of flow variables at their interfaces. Both a multi-domain (continuity explicitly imposed) method in the time domain and a spectral element (continuity implicitly imposed by projecting the governing equation on a vector space of functions continuous at the interfaces) method in the frequency domain will be>presented. For time integration, low-storage Runge-Kutta methods of up to fourth order accuracy for nonlinear systems of ordinary differential equations and optimized for wave propagation are used. Results obtained for spinning mode radiation from engine inlets compare very well with analytical and experimental data. Some practical issues such as automatic grid generation via interaction with commercial packages, radiation boundary conditions and iterative complex matrix solvers versus domain decomposition will also be shortly addressed.