应用极坐标一例

利用极坐标系中径向中速度与横向速度的概念求解运动学中的一个追线问题。     

Transverse radius dependence for transverse velocity and elliptic flow in intermediate energy HIC

The mean transverse velocity and elliptic flow of light fragments (A ≤ 2) as a function of transverse radius are studied for 25 MeV/nucleon ⁶⁴Cu+⁶⁴Cu collisions with impact parameters 3--5 fm by the isospin-dependent quantum molecular dynamics model. By comparison between the in-plane and the out-of-plane transverse velocities, the elliptic flow dependence on the transverse radius can be understood qualitatively, and variation of the direction of the resultant force on the fragments can be investigated qualitatively.     

大气/钢靶板交界处对平行入射聚能射流干扰的数值模拟

利用非线性动力学软件LS-DYNA,对聚能射流平行入射大气/钢靶板交界处的侵彻过程进行了数值模拟.通过分析数值模拟过程和结果,讨论了聚能射流头部速度和碰撞出口处横向速度的变化规律.结果表明:大气/钢靶板交界处不仅降低了聚能射流头部的轴向速度,而且使射流头部产生横向偏移,最大速度达到约1.8 km/s;后续射流横向偏移速...     

Grey spatial solitons due to two-photon photorefractive effect

This paper predicts that grey spatial solitons can exist in two-photon photorefractive materials. In steady state and under appropriate external bias conditions, it obtains the grey spatial soliton solutions of the optical wave evolution equation. The intensity profile, phase distribution,and transverse velocity of these grey solitons are discussed.     

Lagrangian Structure Function＇s Scaling Exponents in Turbulent Channel Flow

The Lagrangian structure function＇s scaling exponents and intermittency of three-dimensional incompressible turbulent channel flow are investigated by using direct numerical simulation. The intermittency in streamwise velocity increments is found to increase in the near-wall region, which can be attributed to the presence of strong mean shear and organized motions in the near-wall region. It is found that the intermittency of transverse velocity increments is weaker than that of longitudinal ones. The present ESS evaluation of ζL（q） for the structure function of the streamwise velocity component in the channel centre is fairly close to experimental estimates of isotropic turbulence.     

几个角动量守恒问题的讨论

本文通过几个实例，讨论了角动量守恒时，质点的径向、横向速度及功与能量问题。     

超相对论Au+Au碰撞中椭圆流的时间依赖

用相对论量子分子动力学(RQMD)模型模拟了质心系束能量为s_NN=200GeV的Au+Au非对心碰撞, 研究了椭圆流对末态粒子冻出时间的关系. 研究了在不同的阶段, 椭圆流对末态粒子位置的关系. 结果表明椭圆流随冻出时间的单调递减, 椭圆流对横向半径的关系随冻出时间发生变化. 用压力梯度对所得结果进行了分析. 径向速度用来表征压力梯度.