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971.
972.
The secondary flow driven by the primary vortex in a cylinder,generating the so called "tea leaf paradox",is fundamental for understanding many natural phenomena,industrial applications and scientific researches.In this work,the effect of wettability on the primary vortex and secondary flow is investigated by the three-dimensional multiphase lattice Boltzmann method based on a chemical potential.We find that the surface wettability strongly affects the shape of the primary vortex.With the increase of the contact angle of the cylinder,the sectional plane of the primary vortex gradually changes from a steep valley into a saddle with two raised parts.Because the surface friction is reduced correspondingly,the core of the secondary vortex moves to the centerline of the cylinder and the vortex intensity also increases.The stirring force has stronger effects to enhance the secondary flow and push the vortex up than the surface wettability.Interestingly,a small secondary vortex is discovered near the three-phase contact line when the surface has a moderate wettability,owing to the interaction between the secondary flow and the curved gas/liquid interface. 相似文献
973.
We prove a form of reflection positivity in planes containing sites for a class of quantum lattice systems. As an application, a proof is given of a phase transition for the Fisher-stabilized Ising antiferromagnet in an external magnetic field with parallel and transverse components, both by the method of infrared bounds and by a suitable version of the Peierls argument. We also discuss the spherical model in an appendix. 相似文献
974.
975.
采用格子Boltzmann方法模拟了在热对流条件下的颗粒沉降问题, 在研究单颗粒在等温流体、热流体和冷流体中运动的基础上, 进一步模拟了两个不同温度的颗粒在流体中的沉降.结果表明:两等温颗粒的沉降方式与雷诺数Re以及格拉晓夫数Gr密切相关, 而两不同温度的颗粒与两等温颗粒的沉降规律有显著不同.无论初始位置如何, 冷颗粒最终总位于热颗粒下方运动, Re较大时, 发生连续的拖曳、接触现象, 而Re较小时, 冷颗粒会以较大的沉降速度远离热颗粒.
关键词:
格子Boltzmann方法
颗粒沉降
热对流 相似文献
976.
Ce0.5Zr0.5O2固溶体的原位拉曼光谱 总被引:11,自引:0,他引:11
控制合成条件以湿化学法制备了Ce-Zr-O(Ce)/n(Zr)=1固溶体,XRD结果证实催化剂前体经923K焙烧后可获得立方相Ce0.5Zr0.5O2固溶体,TE倒固溶体颗粒大小均一、分散、呈纤毛状、在氧化和还原气氛条件下分别对固溶体进行了原位拉曼光谱研究,结果表明,除450-470cm^-1处出现而心立方晶格F2g拉曼地应的强拉曼谱峰外,290-320cm^-1,57-620cm^-1,770- 相似文献
977.
978.
Saburo Higuchi 《Nuclear Physics B》1999,540(3):5677-741
A Hamiltonian cycle of a graph is a closed path that visits every vertex once and only once. It has been difficult to count the number of Hamiltonian cycles on regular lattices with periodic boundary conditions, e.g. lattices on a torus, due to the presence of winding modes. In this paper, the exact number of Hamiltonian cycles on a random trivalent fat graph drawn faithfully on a torus is obtained. This result is further extended to the case of random graphs drawn on surfaces of an arbitrary genus. The conformational exponent y is found to depend on the genus linearly. 相似文献
979.
Xiaoying Han 《Journal of Mathematical Analysis and Applications》2011,376(2):481-493
We study the asymptotic behavior of solutions to the stochastic sine-Gordon lattice equations with multiplicative white noise. We first prove the existence and uniqueness of solutions, and then establish the existence of tempered random bounded absorbing sets and global random attractors. 相似文献
980.
XU You-Sheng LIU Yang YANG Xiao-Feng WU Feng-Min 《理论物理通讯》2008,49(5):1319-1322
To investigate the convection in a porous medium, a horizontal
quiescent layer of one fluid saturating a porous medium heated from bottom is numerically studied using single lattice-Boltzmann method (LBM) and the generalized Navier-Stokes equation proposed by Nithiarasu et al. [P. Nithiarasu, K.M. Seetharamu, and T Sundararajan, Int. J. Heat Mass Trans. 40 (1997) 3955]. Due to the rarefaction, the boundary conditions are considered as both temperature jump and velocity slip. The computational results are validated against the
analytical results, and excellent agreement has been obtained. The
results have shown that the Rayleigh number is increased with
increasing temperature jump, the stabilization effect of
temperature is much more significant than that of velocity slip,
and the computation stability of present model is better than that
of Darcy and Brinkman models. 相似文献