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1.
韩式方 《数学物理学报(B辑英文版)》1992,(2)
The unsteady flow of non-Newtonian fluid is an important problem in the industries of chemistry, polymer, food and power. For Newtonian fluid flow there are some solutions of special cases given in books but no general solution has been obtained. For non-Newtonian fluid there are solutions only for the power law fluid. In the present paper using a variational approach of Kantoroviach an unsteady flow 相似文献
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在本文中,研究了注入轴对称模腔非牛顿流体非定常流动.本文的第二部份研究了上随体Maxwell流体管内热流动.对于注入模腔流动.其本构方程采用幂律流体模型方程.为了避免在表现粘度中温度关系引起的非线性.引进了一特征粘度的概念.描述本力学过程的基本方程是,本构方程、定常状态的运动方程、非定常能量方程及连续方程.该方程组在空间是二维问题,在数学上是三维问题.采用分裂差分格式求得本方程组的数值解答.分裂法曾成功应用于求解牛顿流体问题.在本文中,首次将分裂法成功地应用解决非牛顿流体流动问题.对于圆管内热流,给出了差分格式,使基本方程组化为一个三对角方程组.其结果,给出了不同时刻的模腔内二维温度分布. 相似文献
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韩式方 《数学物理学报(B辑英文版)》1981,(1)
本文从“只有用非线性项才能更好地描述玻尔兹曼碰撞积分的非线性项”的基本思想出发,将逆碰撞积分写成局部麦克斯韦函数 f_e 的幂级数形式,各 f_e~n 项的系数是一速度和宏观量的函数,导出了一种新的气体分子动力论模方程.应用 Chapmann-Enskog 方法求解了本模方程,并订算出普朗特数 P_r=2/3.本模方程应用于研究一维正激波结构问题,用数值方法求得本问题的数值解答.并与实验结果作了比较,其结果良好. 相似文献
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在非平衡气体动力论和稀薄气体动力学的理论研究中,发展了模方程法[1—4]。本文将逆碰撞积分写成f_z~n乘以对应的速度多项式为通项的级数形式,导出了一种新的非平衡气体动力论模方程,并应用该方程研究了冲激波结构问题,取得了良好结果。 相似文献
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In the present investigation the time dependent flow of an Oldroyd fluid B in a horizontal cylindrical pipe is stuided by
the variational analytical approach developed by author. The time dependent problem is mathematically reduced to a partial
differential equation of third order. Using the improved variational approach due to Kantorovich the partial differential
equation can be reduced to a system of ordinary differential equations for different approximations. The ordinary differential
equations are solved by the method of the Laplace transform which is led to an analytical form of the solutions.
Project supported by TWAS and Chinese Academy of Sciences and the National Science Foundation of China 相似文献
8.
一般的流体力学、空气动力学、弹性力学等都是建立在连续介质概念的基础上,不研究构成连续介质的微观粒子的运动状态。随着高空高速飞行、宇航事业的发展,对空间科学的研究以及真空技术的发展,稀薄气体动力学得到了迅速发展。在数百公里以上的高层大气中,气体分子的平均自由程比飞行器的尺寸大得多。在广阔的日地空间里,在无限的宇宙空间中,大多数物质呈稀薄等离子体状态。有时,在一立方公里的空间内只有几十个分子在运动。用一般连续介质概念已不能描述这种运动状态,而必须从微观分析出发,也就是说,要用分子运动论的的方法研究气体的运动状态。 相似文献
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韩式方 《数学物理学报(B辑英文版)》1983,(2)
The concept of a Boundary Layer, as a region adjacent to a solid boundary in which vorticity varies rapidly as a result of viscous convection and diffusion,outside of which the vorticity is zero, was introduced by Prandlt. Some authors have made attempts to extend 相似文献
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Constitutive equation of co-rotational derivative type for anisotropic-viscoelastic fluid 总被引:3,自引:0,他引:3
韩式方 《Acta Mechanica Sinica》2004,20(1):46-53
A constitutive equation theory of Oldroyd fluid B type, i.e. the co-rotational derivative type, is developed for the anisotropic-viscoelastic
fluid of liquid crystalline (LC) polymer. Analyzing the influence of the orientational motion on the material behavior and
neglecting the influence, the constitutive equation is applied to a simple case for the hydrodynamic motion when the orientational
contribution is neglected in it and the anisotropic relaxation, retardation times and anisotropic viscosities are introduced
to describe the macroscopic behavior of the anisotropic LC polymer fluid. Using the equation for the shear flow of LC polymer
fluid, the analytical expressions of the apparent viscosity and the normal stress differences are given which are in a good
agreement with the experimental results of Baek et al. For the fiber spinning flow of the fluid, the analytical expression
of the extensional viscosity is given.
The project supported by the National Natural Science Foundation of China (19832050 and 10372100) 相似文献