Conservation form of Helbing’s fluid dynamic traffic flow model

A standard conservation form is derived in this paper. The hyperbolicity of Helbing’s fluid dynamic traffic flow model is proved, which is essential to the general analytical and numerical study of this model. On the basis of this conservation form, a local discontinuous Galerkin scheme is designed to solve the resulting system efficiently. The evolution of an unstable equilibrium traffic state leading to a stable stop-and-go traveling wave is simulated. This simulation also verifies that the model is truly improved by the introduction of the modified diffusion coefficients, and thus helps to protect vehicles from collisions and avoide the appearance of the extremely large density.     

Helbing流体力学交通流模型的守恒形式

得到了Helbing交通流流体力学模型的标准守恒形式,并证明了模型的双曲性,这对研究模型的解析性质和数值格式至关重要.基于给出的守恒形式,设计了高效求解模型方程的LDG(lo-cal discontinuous Galerkin)格式,并模拟了由不稳定平衡态到稳定的时停时走波的演化.数值模拟也表明,通过扩散系数校正确实使模型得到改进,避免了车辆碰撞和出现极端高密度.     

非谐势阱中玻色-爱因斯坦凝聚的数值计算

从G-P平均势场理论出发,探讨了玻色-爱因斯坦凝聚(BEC)的G-P方程的一维形式,用数值计算方法研究了非谐势阱中非理想玻色凝聚气体的基态和第一激发态解.给出了能量随非线性系数的变化规律.