Steven Jöns

• Doctor of Engineering
• University of Stuttgart

In this paper, a thermodynamically consistent numerical solution of the interfacial Riemann problem for the first-order hyperbolic continuum model of Godunov, Peshkov and Romenski (GPR model) is presented. In the presence of phase transition, interfacial physics are governed by molecular interaction on a microscopic scale, beyond the scope of the m...

In this paper, a thermodynamically consistent solution of the interfacial Riemann problem for the first-order hyperbolic continuum model of Godunov, Peshkov and Romenski (GPR model) is presented. In the presence of phase transition, interfa-cial physics are governed by molecular interaction on a microscopic scale, beyond the scope of the macroscopi...

The ghost fluid method allows a propagating interface to remain sharp during a numerical simulation. The solution of the Riemann problem at the interface provides proper information to determine interfacial fluxes as well as the velocity of the phase boundary. Then considering two-material problems, the initial states of the Riemann problem belong...

In this paper, we consider Riemann solvers with phase transition effects based on the Euler–Fourier equation system. One exact and two approximate solutions of the two-phase Riemann problem are obtained by modelling the phase transition process via the theory of classical irreversible thermodynamics. Closure is obtained by appropriate Onsager coeff...

We present a dynamic load balancing scheme for compressible two-phase flows simulations using a high-order level-set ghost-fluid method. The load imbalance arises from introducing an element masking that applies the costly interface-tracking algorithm only to the grid cells near the phase interface. The load balancing scheme is based on a static do...

The computation of two-phase flow scenarios in a high pressure and temperature environment is a delicate task, for both the physical modeling and the numerical method. In this article, we present a sharp interface method based on a level-set ghost fluid approach. Phase transition effects are included by the solution of the two-phase Riemann problem...

In this paper, we consider Riemann solvers with phase transition effects based on the Euler-Fourier equation system. One exact and two approximate solutions of the two-phase Riemann problem are obtained by modelling the phase transition process via the theory of classical irreversible thermodynamics. Closure is obtained by appropriate Onsager coeff...

The Riemann problem is one of the basic building blocks for numerical methods in computational fluid mechanics. Nonetheless, there are still open questions and gaps in theory and modelling for situations with complex thermodynamic behavior. In this series, we compare numerical solutions of the macroscopic flow equations with molecular dynamics simu...

We study Godunov’s method for diffusion and advection-diffusion problems. The numerical fluxes for the finite volume scheme are based on an approximation of the generalized Riemann Problem. Hereby, approximate Riemann solvers are constructed, which approximate the solutions by a space-time discontinuous Galerkin approach. The implementation to a Go...

This paper describes improvements of a level-set ghost-fluid algorithm in the scope of sharp interface multi-phase flow simulations. The method is used to simulate drop-drop and shock-drop interactions. Both, the level-set and the bulk phases are discretized by a high order discontinuous Galerkin spectral element method. The multi-phase interface a...

We construct an approximate Riemann solver for scalar advection–diffusion equations with piecewise polynomial initial data. The objective is to handle advection and diffusion simultaneously to reduce the inherent numerical diffusion produced by the usual advection flux calculations. The approximate solution is based on the weak formulation of the R...