90 / 2019-10-13 17:30:28

High-fidelity simulations of compressible multi-species and multi-phase flows

High-order Scheme,multi-species flows,Compressible multi-phase flows,hypersonic aerodynamics

We report our recent progress in computational modeling of compressible multi-species and multi-phase flows using high-order or high-resolution numerical methods. These flows, usually encountered in eg. supersonic/hypersonic nonequilibrium aerodynamics, aircraft icing, engine combustion, and high-energy physics, contain discontinues and a broad spectrum of flow features.
To accurately predict the underlying mechanism and resolve the multiscale structures, the computational simualtions of compressible multi-species and multi-phase flows require high-order approxiamtion of the governing equations, which is more challenging than traditional low-order numerical treatments. Here our contributions include the following aspects. First, we have developed a fast high-resolution finite difference for compressible multi-species flows on general curvilinear meshes, and derived a new projection method for Roe-average to aviod spurious oscillations. The resulting method does not violate the free-stream property and has roughly the same efficiency as of the Cartesian-grid finite difference schemes. This method has been applied to study the shock-driven combustion in a highly underexpanded jet and the nonequilibrium hypersonic aerodynamics.
Second, we have proposed a sharp-interface interface-interaction method for compressible multi-phase flows based on high-order schemes. A multi-region level-set technique, which is able to
represent arbitrary number of phases by a single unsigned level-set function combined with an additional phase indicator, is developed to representing the phase interfaces and their evolution. The advection of multiple junctions and topology changes of the interface network are automatically captured. The exchange flux across different materials are calculated by a reduced interface-interaction model to archive high computational efficiency. We test this method by the multi-material shock tube problem, inertial confinement fusion implosion, triple-point shock interaction and shock interaction with multiple bubbles, etc.
Last we will use the mutli-resloution technique to adaptively refine and coarsen the mesh when simualting those flows. This technique, based on wavelet analysis, contains a projection and prediction operations, and show relatively higher compression rate and speedup than the tradional AMR technique.