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1、湘潭大学 硕士学位论文 用DHR型k-模型对逆与顺压梯度内部紊流的数值仿真 姓名：蒋紫筠 申请学位级别：硕士 专业：计算数学 指导教师：何永森 20070430 ? ?DHR?k ?BFC?(? ?)?80?4? ? ? ?1.16105?2.93105? ? ? ? ? ?u? ?k? ?u?p?k? ?t? ? ? ?: DHR?k ?BFC? ? I Abstract Fully developed incompressible turbulent fl ow with adverse and favorable pressure gradient in a conical diff u
2、ser and outlet pipe having a total divergence of 80and an area ratio of 4:1 has been simulated by a DHR k turbulence model and its wall function?BFC (Boundary -Fitted Coordinates) approach. The research has been done for pipe entry Reynolds numbers of 1.16 105and 2.93105 .Based on the near wall dens
3、eness model radial fi tted-body nonuniform grid system ,The mesh fi gures of physical plane have been plotted .Analyzing the eff ection of calculated results under diff erent calculated conditions,such as diff erent time step,relaxation coeffi cient,numerical methods and wall diff erence methods.The
4、 calculation results of the mean velocity and turbulence energy have been given,and they have been analysed and compared with the experimental re- sults respectively.At the same time,The distribution of the main fl ow parameters in a conical diff user and outlet pipe,such as the mean fl ow velocity,
5、the mean pres- sure,turbulence energy,turbulence dissipation and eddy viscosity coeffi cient have been given.The eff ective degree of calculation effi ciency and calculation accuracy has been studied under the diff erent calculated conditions and draw corresponding conclusions,and they have off ered
6、 reference for science research and engineering techniques actual application,possessing theoretical and actual meaning. Keywords: k turbulence model;wall functionBFC method; con- ical diff user and outlet pipe;adverse and favorable pressure gradient; numerical simulation;time step;relaxation coeffi
7、 cient;numerical meth- ods II ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1 ? ? ? ?(?)? ? ? ? 2 ? ? ? ? ? ? ? ? ? ? ? ?(CFD, Computational Fluid Dynamics)? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1.? ? 1 2.? ?(?)? ? 3.? ? ? 4.? ? ? ? 5.? ? 6.? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?- ?(N-S?)? ? ? ? ? ?0? ? 3 ? 2 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
