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A lattice Boltzmann equation model has been developed by using the equilibrium distribution function of the Maxwell-Boltzmann-like form, which is third order in fluid velocity uα. The criteria of energy conservation between the macroscopic physical quantities and the microscopic particles are introduced into the model, thus the thermal hydrodynamic equations containing the effect of buoyancy force can be recovered in terms of the Taylor and Chapman-Enskog asymptotic expansion methods. The two-dimensional thermal convection phenomena in a square cavity and between two concentric cylinders have been calculated by implementing a heat flux boundary condition. Both numerical results are in good agreement with the conventional numerical results. 相似文献
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根据微观和宏观之间的质量、动量、能量守恒准则和在原格子Boltzmann模型基础上,建立了几个新的格子Boltzmann模型,使得在外力场中的格子Boltzmann模型得到进一步完善.通过还原宏观流体力学方程,捕捉到了浮力强迫系数与Grashof数之间的关系.所得动量方程和Navier Stokes方程相比,在黏性输运项上有明显的改进,说明黏性应力不但与流体的速度梯度和流体的压缩性有关,而且还与非定常的内能梯度和动量通量有关.该模型对非等温流场的数值结果证明了其具有很好的数值稳定性和适用性.
关键词:
Boltzmann模型
平衡分布函数
流体力学方程 相似文献
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十三点格子Boltzmann模型仿真 总被引:2,自引:1,他引:1
格子气和格子Boltzmann方法的迅速发展提供了一类求解流体力学问题的新方法。格子Boltzmann方法在保留了格子气模型优点的同时,克服了它的不足之处。本文讨论了一种三迭加HPP十三点模型,通过选择适当的平衡分布及参数,并用Chapman-Enskog展开和多尺度技术导出了Navier-Stokes方程。在微机上模拟了空腔流的流动问题,并与传统方法的计算结果进行了比较,结果表明该模型能较好的模拟复杂流动现象,并具有较好的工程应用背景。 相似文献
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科里奥利力在流量测量中的应用 总被引:3,自引:0,他引:3
本文阐述了如何利用科里奥利力精确测量管道中介质的质量流量的原理和方法,并描述了利用科里奥利力的质量流量计的类型和典型结构及其发展情况. 相似文献
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With the discrete method of the hexagonal cell and three different velocities of particle population in each cell, a two-dimensional lattice Boltzmann model is developed in this paper.[1,2] The collision operator in the Boltzmann equation is expanded to fourth order using the Taylor expansion.[3,4] With this model, good results have been obtained from the numerical simulation of the reflection phenomenon of the shock wave on the surface of an obstacle, and the numerical stability is also good. Thus the applicability of the D2Q 19 model is verified. 相似文献
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指出了转盘上的观者在观测一个相对于他运动的质点时,该质点是否受到科氏力只取决于该观者是否有自转而与转盘的转动(即观者的“公转”)无关. 相似文献
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本文采用Klimontovich方法导出了相对论磁化等离子体的广义玻尔兹曼方程碰撞项,计算出带电粒子间的感应电磁力对碰撞项的贡献。 相似文献