Interaction of incompressible and compressible MHD fluctuations on a one-dimensional plasma inhomogeneity, transverse to the magnetic field, is considered in the three-dimensional regime. An initially incompressible (Alfvénic) MHD fluctuation generates, by linear coupling, compressible (magnetoacoustic) fluctuations. In the initial stage of the interaction, the efficiency of the coupling is enh...

This paper presents a novel hybrid method for solving the low-Mach-number equations for inviscid flow supplemented with long wavelength acoustics as computed by solving the fully compressible Euler equations. Contrary to previous existing methods, the novelty of the present strategy is that the fully compressible equations are solved without any approximation, and that an adaptive mesh refineme...

This work focuses on numerically modelling the dynamics of a single phase fluid at varying densities and pressures. We explore the potential of incompressible flow simulation methods in modelling compressible flow, with an eye towards computer animation applications. The methods developed capture the interesting thermodynamic effects of compressible flow, and reduce to the standard Marker and C...

This paper presents asymptotically stable schemes for patching of nonoverlapping subdomains when approximating the compressible Navier–Stokes equations given on conservation form. The scheme is a natural extension of a previously proposed scheme for enforcing open boundary conditions and as a result the patching of subdomains is local in space. The scheme is studied in detail for Burgers’s equa...

In this paper, we first generalize the classical results on Cauchy problem for positive symmetric quasilinear systems to more general Besov space. Through this generalization, we obtain the local well-posedness with initial data in the space B d 2 +1 2,1 (R ) which has critical regularity index. We then apply these results to give an explicit characterization on the Isentropic approximation for...

In this paper we compare fully compressible (Meakin & Arnett 2006a,b) and anelastic (Kuhlen, Woosley, & Glatzmaier 2003) simulations of stellar oxygen shell burning. It is found that the two models are in agreement in terms of the velocity scale (vc ∼ 10 7 cm/s) and thermodynamic fluctuation amplitudes (e.g., ρ/〈ρ〉 ∼ 2 × 10) in the convective flow. Large fluctuations (∼11%) arise in the compres...

In this paper, we derive Hybrid, Bayesian and Marginalized Cramér-Rao lower bounds (HCRB, BCRB and MCRB) for the single and multiple measurement vector Sparse Bayesian Learning (SBL) problem of estimating compressible vectors and their prior distribution parameters. We assume the unknown vector to be drawn from a compressible Student-t prior distribution. We derive CRBs that encompass the deter...

In this paper we study the self-propelled motion of a single deformable body in a viscous compressible fluid which occupies whole 3-dimensional Euclidean space. The considered governing system for the fluid is the isentropic compressible Navier-Stokes equations. The main result of this paper is the existence of a weak solution on a time interval (0,+∞).

We discuss the matrix-free implementation of Discontinuous Galerkin methods for compressible flow problems, i.e. the compressible Navier-Stokes equations. For the spatial discretization the CDG2 method and for temporal discretization an explicit Runge-Kutta method is used. For the presented matrix-free approach we discuss asynchronous communication, shared memory parallelization, and automated ...

We present a technique for converting continuous gray-scale images to halftone (black and white) images that lend themselves to lossless data compression with compression factor of three or better. Our method involves using novel halftone mask structures which consist of non-repeated threshold values. We have versions of both dispersed-dot and clustered-dot masks, which produce acceptable image...