Influence of linear and non-linear constitutive models on thermoacoustic waves in an enclosure

w The problem of unsteady compressible fluid flow in an enclosure induced by thermoacoustic waves is studied numerically. Full compressible set of Navier-Stokes equations are considered and numerically solved by boundary-domain integral equations approach, coupled with wavelet compression and domain decomposition to achieve numerical efficiency. The thermal energy equation is written in its most general form including the Rayleigh and reversible expansion rate terms. Both the classical Fourier heat flux model and wave heat conduction model are investigated. The momentum flux is modelled using standard Newtonian viscous model and linear viscoelastic Maxwell model. The velocity-vorticity formulation of the governing Navier-Stokes equations is employed, while the pressure field is evaluated from the corresponding pressure Poisson equation. Material properties are taken to be for the perfect gas and assumed to be pressure and temperature dependent.