For dynamic traffic assignment problem in road network,we adopt a conserved higher-order (CHO) model for modeling and numerical study. The CHO model is combined with dynamic network loading (DNL) model,and the dynamic network loading model is analyzed through variational inequalities. In numerical simulation,the first-order finite volume method was used to solve the CHO model,and a gradient descent method was used to solve the variational inequality problem of the dynamic network loading model iteratively. Finally,a distribution equilibrium was achieved under the dynamic user optimal condition. The numerical results show that the combination of CHO model and DNL model is feasible for solving the dynamic traffic assignment problem.

To investigate injury of windblast at high speed,flow around a seat occupant is simulated in a scale adaptive simulation turbulence model. Numerical simulations agree well with wind tunnel experiments at Mach number 0.6 and angles of attack from -90° to 90°. Flow around seat occupant without protection is simulated. Injury of pilot during high speed ejection is investigated. It shows that high pressure zones load on pilot are face,thorax,abdomen,inside of upper arm and windward side of calves. As pitch angle increases pressure distribution on each part can improve.

Newton-Raphson iteration is used in semi-classical model of carbon nanotube field effect transistors(CNTFET) based on ballistic transport for self-consistent potential.In each iteration re-integration of state density is requred.Support vector regression (SVR) is applied for the relationship of self-consistent potential and carrier density.Numerical integrations are avoided.And gradient descent algorithm (GDA) is used to get self-consistent potential.It shows that compared with Newton-Raphson iteration,the proposed method reduces computation effectively while maintains high accuracy.It lays theoretical foundation for designing and applying CNTFET devices in large scale integrated circuits.

Two influential traffic flow models formulated by Zhang H M and Wu Zheng are improved to include the lane-change problem,and the relations between the two models and the traditional speed-density hypothesis model are discussed.Runge-Kutta Discontinuous Galerkin Finite Element Method is generalized and applied to these three models for numerical solutions through which the traffic signal problem,lane-change problem and non-equilibrium traffic flow phenomena are well simulated.

By taking the numerical method and traffic phenomena into account, reasonable improvement is attained on the kinetics equation of the L-W theory. The comparison between what is deduced from the original model by means of characteristics and discontinuity analysis and what is shown by the numerical results of the improved model is made, which further reveals that the latter is the approximation of the former and that such results are convincing. Numerical examples include such problems as red-and-green and traffic accidents, which concern mixed density distribution from the minimum to the maximum, lane changing and a quick density increase or decrease on the boundary and which are also considered most challenging in the field.

It proposes a viewpoint that the finite element method (FEM) might be well used in traffic flow models, among which a newly developed dynamics model is elaborated. In the discussion, it is foreseen that the new model is fundamentally sound and has much advantage over some well known traditional ones. In the FEM solution, the weak form of the model is properly constructed by means of weight residual method and equations for weak solution are given. Finally, it achieves some favorable results in the numerical simulation and this, in a degree, makes the argument convincing.

Upwind TVD scheme is used to solve laminar, 2D fully N-S equations.A shock diffracted by a cylinder or square cylinder along hydrogen air interface, and mixing enhancement in a shear flow are numerically studied.The results indicate that the shock travels faster in hydrogen.An adjustable shock and a swirling ovrtex appear in the shear region.After the swirling vortex impacts the cylinders, a reflected shock is formed, and hydrogen diffuses downstream in the region near cylinder walls.Contact surfaces are deformed and another vortex is generated.The distribution of hydrogen shows that the mixing is enhanced effectively by inserting cylinders along the interface, expecially for a square cylinder.The transition from RR to MR can be found for shocks traveling both in air and in hydrogen for a cylinder.Two Mach stems will transmit each other at the downstream.But in the case of a square column, the shock is almost not affected along the lower wall but Mach reflection takes place along the upper wall, then a diffracted shock and a Mach stem transmit each other finally.For both cases, the detached shock occurs on the right of cylinders.Similar shock structures arise, and contributions of cylinder shape are eventually forgotten.

The helical instability of an arc column with electrical conductivity of the parabolic distribution,transparent radiation of the parabolic distribution and constant reaction heat is discussed in an axial magnetic field.The magnetohydrodynamic equations serve as the starting point of the theory.In an electrostatic approximation and a linear time dependent perturbation theory,the perturbation equations for the arc column movement are deduced.Solutions of these equations are obtained analytically,from which the stability limit of the cylindrical arc and the growth rate of the helical instability are given.In comparison with the results without reaction heat,it is found that the reaction heat increases the helical instability.

The helical instability of an arc column with electrical conductivity of the parabolic distribution and macro velocity is discussed in an axial magnetic field. The magnetohydrodynamic equations serve as the starting point of the theory, in an electrostatic approximation and a linear time dependent perturbation theory, the perturbation equations for the arc column movement are deduced. Solutions of these equations are obtained analytically, from which the stability limit of the cylindrical arc and the growth rate of the helical instability are given.