Unsteady flow characteristics of particles in plumes are studied with direct simulation Monte-Carlo method (DSMC) in an 8×10^-6 s period. Dissociation model, recombination model and charge exchange model are included based on Bird's chemical reaction models. Molecular hydrogen H₂, atomic hydrogen H, atomic metal X, ion H₂⁺ and ion H⁺ are included. Influence on density distribution of particles in the field due to dissociation and recombination is studied. It shows that the number density of molecular hydrogen H₂ decreases and the number density of atomic H increases since dissociation rate of molecular hydrogen H₂ is faster than recombination of atomic H in the flow field. A charge exchange model is added in dissociation and recombination models. It shows that the number density of ion H₂⁺ decreases and the number density of ion H⁺ increases obviously in charge exchange model.

Dynamic yield behavior of magnetorheological fluids is investigated by upscaling information of microscale interaction between particles, employing a large-scale molecular dynamical simulation technique, to macroscale bulk behavior. We conduct a stochastic muhiscale model for dynamic yield of magnetorheological fluids based on equivalence of system energy at different scales. It is revealed that the dynamic yield exhibits nonlinear and stochastic fluctuations due to heterogeneity of sequence and number of cluster-sheet reconstructions under shear fields loading, as well as Brownian motion of suspensions with initial random conditions. Meanwhile, we investigate fluctuation of microscale particle motions, relationship between stress and strain, and constitutive relationship of shear rate. It is noted that the microscale thermal fluctuation is far more than macroscalc variations since the upscaling from microscale to macroscale results in degradation of fluctuations. Besides, the macroscale variations relies on external magnetic field as in the constitutive relationship of shear rate, i.e. Bingham model, which is supposed to be considered in the design and optimization of magnetorheological devices.

Finite element equations to calculate current and temperature fields of aluminum reduction cells are deduced using Galerkin method.The finite element model of anode and molten electrolyte is built according to multiple elements and multiple properties of ANSYS software.With reasonable assumption of boundary conditions,the current and temperature fields of 160?KA prebaked reduction cells are computed and the temperature,voltage and electric current distributions of the cells are analyzed.The simulation results of the model well coincide with the design data,and therefore provide foundations for optimizing current aluminum electrolysis cells and developing new type cells.

A Fast grid generation procedure named parabolic equation method for complex aircraft is developed. Grid is obtained by marching from body surface to outer boundary. Successful control of grid orthogonality on body is achieved by means of the introduction of algebraic grid prediction. A numerical algorithm based on a finite volume explicit scheme is employed for calculating transonic flow around a realistic aircraft configuration. Comparisons of the computational results with experimental data show very good agreement in terms of trends.

A body-fitted orthogonal grid around complex configurations including wing,body,pylon and nacelle has been suc-cessfully generated by applying the multi-block grid technique and the method of solving elliptic and parabolic partial differential e-quations.The transonic flow field and aerodynamic characteristics of the advanced twin engine transport aircraft are also simulated numerically by using finite volume methods to solve the Euler equations with high efficiency,and the viscous effect of wing bound-ary layer is considered.Results of the calculation show that pylon and nacelle have significant effect on the supercritical wing aerody-namic characteristics.the numerical results are in good agreement with the experimental wing surface pressure distribution data.

A simulation method has been developed for the analysis of powered engines,whose components include the outer cowl,spinner,fan face,fan exit plane,and core cowl geometry.In the simulation,either the mass flux or the static pressure can be prescribed at the fan face.The total pressure,total temperature,flow direction and the bypass ratio are specified at the turbine or fan exit plane,and the exhaust plume emerges naturally as part of the global solution.Comparison of numerical results with test data shows a very good agreement.