Three-dimensional CFD simulations with large displacement of the geometries using a connectivity-change moving mesh approach

This paper deals with three-dimensional (3D) numerical simulations involving 3D moving geometries with large displacements on unstructured meshes. Such simulations are of great value to industry, but remain very time-consuming. A robust moving mesh algorithm coupling an elasticity-like mesh deformation solution and mesh optimizations was proposed in previous works, which removes the need for global remeshing when performing large displacements. The optimizations, and in particular generalized edge/face swapping, preserve the initial quality of the mesh throughout the simulation. We propose to integrate an Arbitrary Lagrangian Eulerian compressible flow solver into this process to demonstrate its capabilities in a full CFD computation context. This solver relies on a local enforcement of the discrete geometric conservation law to preserve the order of accuracy of the time integration. The displacement of the geometries is either imposed, or driven by fluid–structure interaction (FSI). In the latter case, the six degrees of freedom approach for rigid bodies is considered. Finally, several 3D imposed-motion and FSI examples are given to validate the proposed approach, both in academic and industrial configurations

Multi-scales Approximations of Thin Flows for Curved Topography

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

Formation and Coarsening of Roll Waves in Shear Flows down an Inclined Rectangular Channel

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

Implicit linearity preservation type schemes for moving meshes

AbstractWe are concerned with the accurate implicit approximation of compressible flows in a fixed and moving mesh context, such as piston engine flows. Geometries are commonly complex and flows compressible. Therefore, it is convenient to develop the numerical approach in the context of a space-time finite-volume formulation for unstructured meshes. The hyperbolic flux is obtained by a generalized Riemann solver taking into account the mesh motion. Using the linearity preservation property we propose a new class of stable implicit schemes developing low numerical viscosity. These schemes can be viewed as a correction of the usual MUSCL flux, induced by the time derivative and mesh motion. Accurate numerical results are obtained for transonic (shock tube) as well as low Mach number flows (diesel engine). It is numerically proved, that for large time steps, those approximations can be as accurate as some explicit schemes. The proposed schemes, due the compactness of the stencils, are well adapted for parallelization strategy

On the Behaviour of Upwind Schemes in the Low Mach Number Limit: A Review

International audienceThis work is devoted to a review of different modifications proposed to enable compressible flow solvers to compute accurately flows near the incompressible limit. First the reasons of the failure of upwind solvers to obtain accurate solutions in the low Mach number regime are explained. Then different correction methods proposed in the literature are reviewed and discussed. This work concludes by some numerical experiments to illustrate the behaviour of the different methods

Formation and coarsening of roll-waves in shear shallow water flows down an inclined rectangular channel

International audienc