The goal of this work is to investigate methods for simulating turbulent supersonic flows that include shock waves. Several different types of previously proposed characteristic filters, including total variation diminishing (TVD), monotone upstream-centered scheme for conservation laws (MUSCL), and weighted essentially non-oscillatory (WENO) filters, are investigated in this study. Similar to ...

The aim of this article is a qualitative analysis of two modern finite volume (FVM) schemes. First one is the so called Modified Causon’s scheme, which is based on the classical MacCormack FVM scheme in total variation diminishing (TVD) form, but is simplified in such a way that the demands on computational power are much smaller without loss of accuracy. Second one is implicit WLSQR (Weighted ...

INTRODUCTION Due to drug-drug interactions of HIV- and HCV-specific antivirals when initiating an HCV-therapy, the antiretroviral therapy (ART) often has to be changed. The spectrum of applicable antiretrovirals is small, therefore many patients were switched to raltegravir/truvada (RAL/TVD) in our cohort. Due to the relatively low genetic barrier of RAL, this regimen may be endangered to fail,...

There is a wide range in the reported photon tenth value distance (TVD) in the maze of high-energy linear accelerator vaults. In order to gain insight into the appropriate use of the TVD value during door design, we performed measurements of the photon dose in the maze of four vaults. In addition, our study represents the first to describe a scenario where an inner borated polyethylene (BPE) do...

Relativistic temperature of gas raises the issue of the equation of state (EoS) in relativistic hydrodynamics. We study the EoS for numerical relativistic hydrodynamics, and propose a new EoS that is simple and yet approximates very closely the EoS of the single-component perfect gas in relativistic regime. We also discuss the calculation of primitive variables from conservative ones for the Eo...

A novel numerical formulation of the two-phase macroscopic balance equations governing the flow field in incompressible porous media is presented. The numerical model makes use of the Weighted Average Flux (WAF) method and Total Variation Diminishing (TVD) flux limiting techniques, and results in a second-order accurate scheme. A shock tube study was carried out to examine the interaction of a ...

A vertex centred Finite Volume algorithm is presented for the numerical simulation of fast transient dynamics problems involving large deformations. A mixed formulation based upon the use of the linear momentum, the deformation gradient tensor and the total energy as conservation variables is discretised in space using linear triangles and tetrahedra in two-dimensional and three-dimensional com...

This paper presents a chemical species transport model to account for variable composition and gas properties along the flow path in internal combustion engines. It is described the numerical solution to adapt the gas dynamic model to chemical species transport in boundary conditions by means of the Method of Characteristics and in volumes by means of a filling and emptying model. The performan...

A conservative modification to the ghost fluid method (GFM) is developed for compressible multiphase flows. The motivation is to eliminate or reduce the conservation error of the GFM without affecting its performance. We track the conservative variables near the interface and use this information to modify the numerical solution when the interface has passed the cell. The modification procedure...

2D Total Variation Denoising (TVD) is a widely used technique for image denoising. It also an important nonparametric regression method estimating functions with heterogenous smoothness. Recent results have shown the TVD estimator to be nearly minimax rate optimal class of bounded variation. In this paper, we complement these worst case guarantees by investigating adaptivity which are piecewise...