Simulation of Axisymmetric Incompressible Flows UsingSemiclassical Lattice Boltzmann Method

• Main Authors: Yao-Tien Kuo, 郭耀天
• Other Authors: 楊照彥
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/36304923502252835683

碩士 === 臺灣大學 === 應用力學研究所 === 98 === In the last decade, Lattice Boltzmann Method, an useful and powerful tool for general fluid flow simulation, has been developed. The three-dimensional axisymmetric pipe flow of gas of arbitrary statistics in the slip and transition regimes as characterized by the Knudsen number are studied using a newly developed semiclassical lattice Boltzmann method. The semiclassical lattice Boltzmann method is derived by directly projecting the Uehling-Uhlenbeck Boltzmann-BGK equations onto the tensor Hermite polynomials using moment expansion method. To take into account the slip motion at wall surface, the Maxwellian scattering kernel is adopted to model the gas surface interactions with an accommodation coefficient. The mass flow rates and the velocity profiles are calculated for the three particle statistics over the slip and transition regimes Knudsen numbers. The results indicate that the Knudsen minimum can be captured and distinct characteristics of the effect of quantum statistics can be delineated. When the fluid flows through a sphere, it will generate vortices behind the sphere. We compare the difference of vortices under the simulation of kinds of statistic models. We change the Reynolds number and compare the change of vortex under the same statistic model. Eventually,we compare the results of three-dimensional axisymmetric sphere flow and two-dimensional circular cylindrical flow and the three-dimensional relieving effect is illustrated.