This work extends the idea of the traditional complex-amplitude expanded phase field crystal (APFC) model using the Ginzburg-Landau approach. A fast structural APFC model is proposed as a quick and effective method for describing different crystal structures. Taking square and rectangular phases as examples, we systematically determine the structure-dependent parameters in the fast structure APFC model and validates its effectiveness through numerical simulations. In particular, when dealing with rectangular phases, it is found that this method not only solves the stability problem of the rectangular phase but also describes the structural phase transition between rectangular and orthorhombic layered phases, demonstrating the capability of the model in describing multiple structural phase transitions. Finally, through simulating the classic rotation-shrinking of a circular grain, we confirm the ability of the model for correctly predicting physical laws and reveal the roles of different crystal symmetries on the rotation-shrinking behavior of the grain. The proposed method in this paper can effectively promote the application of APFC models in the simulation research of more and larger material systems.

A shock-pinned random projection method( SRPM) is proposed. To overcome difficulty of multidirectional propagation,local random projection is applied by introducing a shock indicator along with proper rules for choosing local projection zones around shocks in each reaction step. Numerical experiments are presented. It shows that SRPM is appropriate for detonation waves with multi-directional propagation,which is high-efficient in solving stiff reactive equations and extensible to 3D situations.

A variable-scale lattice gas automata model for gas-solid two-phase flow is established based on lattice gas automata (LGA)in which macroscopic behavior is described with microscopic gas-solid interactions.A two-dimensional flow field is divided into two.deck hexagon laRiees with different scales,where solid particles and gas pseudo-particles are aligned in lattices for solid and gas respectively.In addition to basic LGA rules.collision and propagation rules ale specifically designed for gas-solid systems,as well as additional evolution rules.A statistical method of macroscopic properties and conversion between model parameters and hydrodynamic properties based on similarity principle aIe established. Simulations of dynamic behaviors of gas-solid two-phase flow in a bubbling fluidized bed with this model show good agreement with experiments as well as simulation results with a two-fluid model.It has less average deviation,which validates the proposed model.

Massively parallel numerical simulation of a kerosene-fueled scramjet on national MPP computer with 1024 CPUs is presented.A self-developed software AHL3D is employed.Reynolds averaged N-S equations are adopted in governing equations.Inviscid flux is computed with Steger-Warming flux-splitting scheme.Turbulent effects are studied in a k-ω two-equation turbulence model.Kerosene is replaced by a simple surrogated fuel of n-decane.Computed wall pressure along combustor exhibits good agreement with measured data.Computation shows that cavity provides main ignition zone and flame holder,and recirculation zone resulting from fuel injection contributes to flame stability.It indicates that the AHL3D code and methodologies can be used to simulate complicated flow patterns in kerosene-fueled scramjets.