Relative to the full compressible flow equations, sound-proof models filter acoustic waves while maintaining advection and internal waves. Two well-known sound-proof models, an anelastic model by Bannon and Durran’s pseudo-incompressible model, are shown here to be structurally very close to the full compressible flow equations. Essentially, the anelastic model is obtained by suppressing ∂tρ in...

In this study we propose a new numerical algorithm for droplet-laden turbulent channel flow with phase transitions at low Mach numbers. The carrier gas is treated as compressible flow. In order to avoid very small time steps at low Mach numbers that would arise from stability requirements associated with explicit time-stepping we propose a new semi-explicit time integration method, applied to t...

A new ideal magnetohydrodynamic instability is presented. It is shown that linear incompressible Alfvénic disturbances can get over-reflected and exponentially amplified in compressible plasma flows. A simple and transparent stability criterion for a two-layer model is derived. The instability does not require a shear in the flow and may arise for rather moderate sub-Alfvénic flow speeds. It is...

This contribution illustrates the application of preconditioner updates as in [2] to model problems from compressible flow, that represent a broad range of typical sequences of nonsymmetric linear systems. There, a typical technique is freezing with periodic recomputation of ILU decompositions [3]. This can be improved by updating between refactorizations. In particular, the extension to block ...

We apply the gas-kinetic scheme (GKS) for the direct numerical simulations (DNSs) of compressible decaying homogeneous isotropic turbulence (DHIT). We intend to study the accuracy, stability, and efficiency of the gas-kinetic scheme for DNS of compressible homogeneous turbulence depending on both flow conditions and numerics. In particular, we study the GKS with multidimensional, quasi-one-dime...

Vortex methods have become useful tools for the computation of incompressible fluid flow. In this work, a vortex particle method for the simulation of unsteady two-dimensional compressible flow is developed. By decomposing the velocity into irrotational and solenoidal parts, and using particles that are able to change volume and that carry vorticity, dilatation, enthalpy, entropy and density, t...

This article deals with the numerical solution of compressible turbulent flows in aerodynamics. Compressible turbulent flow is described by the system of Favre averaged Navier-Stokes equations, which are closed by the explicit algebraic Reynolds stress model (EARSM) of Wallin and Johansson. The averaged Navier-Stokes equations together with EARSM model of turbulence are discretized by the finit...

In this work, statistical properties of compressible hydrodynamic and magnetohydrodynamic turbulence are studied using direct numerical simulations. The properties of turbulent flows change when average flow velocities within the turbulence exceed the speed of sound in the medium. High flow velocities lead to the formation of shocks, and some of the base assumptions of turbulence theories of in...