On the basis of the vector formula of the Newton’s law for a viscous liquid and the integrated vector form of the equation of an impulse for a viscous liquid for resistance and carrying power of a profile of any form...On the basis of the vector formula of the Newton’s law for a viscous liquid and the integrated vector form of the equation of an impulse for a viscous liquid for resistance and carrying power of a profile of any form and the big length dependences are found in a stream. Application of the found dependences at a circulating flow of the cylinder located across a stream is showed. The analysis of a tensor of viscosity for laminar and turbulent flow is carried out.展开更多
A new eddy viscosity modelling of turbulence is proposed in ref. [1], whose characteristicsexpress the anisotropy of the turbulence stress. In ref. [1], the way of proposing somedistributional laws of the eddy viscosi...A new eddy viscosity modelling of turbulence is proposed in ref. [1], whose characteristicsexpress the anisotropy of the turbulence stress. In ref. [1], the way of proposing somedistributional laws of the eddy viscosity tensor components is found from experimental re-sults for elementary flow of each kind of shearing flow, and then we can forecast thecomplicated shearing flows more accurately. In this way, the distributional laws of the ed-展开更多
A transonic turbulent separation flow in a converging-diverging transonic diffuser was studied,when there existed a separation bubble on the top wall of the diffuser triggered by strong shock-wave-boundary-layer-inter...A transonic turbulent separation flow in a converging-diverging transonic diffuser was studied,when there existed a separation bubble on the top wall of the diffuser triggered by strong shock-wave-boundary-layer-interaction(SWBLI).To capture the essential behavior of this complex flow,the current study utilized an anisotropic turbulence model developed on the basis of a statistical partial average scheme.The first order moment of turbulent fluctuations,retained by a novel average scheme,and the turbulent length scale,can be determined from the momentum equations and mechanical energy equation of the fluctuation flow,respectively.The two physical quantities were readily used to construct the nonlinear anisotropic eddy viscosity tensor and to significantly improve the computational results.Comparisons between the computational results and experimental data were carried out for velocity profiles,pressure distribution,skin friction coefficient,Reynolds stress as well as streamline vectors distribution.Without using any empirical coefficients and wall functions,the numerical results were in good agreement with the available experimental data,further confirming that the nonlinear anisotropic eddy viscosity tensor is the decisive factor for the success of the computational results.展开更多
1 The Eddy Viscosity Is a Fourth-order Tensor In 1877 Boussinesq proposed that turbulence stress be proportional to the average velocity gradient.He introduced the concept of eddy viscosity coefficient and described t...1 The Eddy Viscosity Is a Fourth-order Tensor In 1877 Boussinesq proposed that turbulence stress be proportional to the average velocity gradient.He introduced the concept of eddy viscosity coefficient and described the turbulence stress展开更多
文摘On the basis of the vector formula of the Newton’s law for a viscous liquid and the integrated vector form of the equation of an impulse for a viscous liquid for resistance and carrying power of a profile of any form and the big length dependences are found in a stream. Application of the found dependences at a circulating flow of the cylinder located across a stream is showed. The analysis of a tensor of viscosity for laminar and turbulent flow is carried out.
基金Project supported by the National Natural Science Foundation of China.
文摘A new eddy viscosity modelling of turbulence is proposed in ref. [1], whose characteristicsexpress the anisotropy of the turbulence stress. In ref. [1], the way of proposing somedistributional laws of the eddy viscosity tensor components is found from experimental re-sults for elementary flow of each kind of shearing flow, and then we can forecast thecomplicated shearing flows more accurately. In this way, the distributional laws of the ed-
基金Aerospace Power Foundation(6141B09050397)Foudamental Reasearch Foundation of North China University of Technology(110052971921/042).
文摘A transonic turbulent separation flow in a converging-diverging transonic diffuser was studied,when there existed a separation bubble on the top wall of the diffuser triggered by strong shock-wave-boundary-layer-interaction(SWBLI).To capture the essential behavior of this complex flow,the current study utilized an anisotropic turbulence model developed on the basis of a statistical partial average scheme.The first order moment of turbulent fluctuations,retained by a novel average scheme,and the turbulent length scale,can be determined from the momentum equations and mechanical energy equation of the fluctuation flow,respectively.The two physical quantities were readily used to construct the nonlinear anisotropic eddy viscosity tensor and to significantly improve the computational results.Comparisons between the computational results and experimental data were carried out for velocity profiles,pressure distribution,skin friction coefficient,Reynolds stress as well as streamline vectors distribution.Without using any empirical coefficients and wall functions,the numerical results were in good agreement with the available experimental data,further confirming that the nonlinear anisotropic eddy viscosity tensor is the decisive factor for the success of the computational results.
基金Project supported by the National Natural Scienoe Foundation of China.
文摘1 The Eddy Viscosity Is a Fourth-order Tensor In 1877 Boussinesq proposed that turbulence stress be proportional to the average velocity gradient.He introduced the concept of eddy viscosity coefficient and described the turbulence stress
