Turbulent features of streamwise and vertical components of velocity in the negative transport region of asymmetric plane channel flow have been studied experimentally in details. Experiments show that turbulent fluct...Turbulent features of streamwise and vertical components of velocity in the negative transport region of asymmetric plane channel flow have been studied experimentally in details. Experiments show that turbulent fluctuations in negative transport region are suppressed, and their probability distributions are far from Gaussian. Besides, the skewness factors attain their negative maxima at the position of the maximum mean velocity, whereas the flatness factors attain their positive maxima at the same position.展开更多
The turbulent passive scalar fluxes were studied by separately considering the contributions of small eddy motions and large eddy ones. Explicit algebraic approximation was achieved for both small eddy and large e...The turbulent passive scalar fluxes were studied by separately considering the contributions of small eddy motions and large eddy ones. Explicit algebraic approximation was achieved for both small eddy and large eddy scalar fluxes. Especially, the large eddy scalar flux was modelled with complex diffusivity. The singular difficulties in usual algebraic scalar models, do not occur any more in this model. In addition, this new model provides a new way to reasonably describe the negative transport phenomena appearing in asymmetric turbulent flows.展开更多
文摘Turbulent features of streamwise and vertical components of velocity in the negative transport region of asymmetric plane channel flow have been studied experimentally in details. Experiments show that turbulent fluctuations in negative transport region are suppressed, and their probability distributions are far from Gaussian. Besides, the skewness factors attain their negative maxima at the position of the maximum mean velocity, whereas the flatness factors attain their positive maxima at the same position.
基金The project supported by the National Natural Science Foundation of China(Grant No.1 9872042)
文摘The turbulent passive scalar fluxes were studied by separately considering the contributions of small eddy motions and large eddy ones. Explicit algebraic approximation was achieved for both small eddy and large eddy scalar fluxes. Especially, the large eddy scalar flux was modelled with complex diffusivity. The singular difficulties in usual algebraic scalar models, do not occur any more in this model. In addition, this new model provides a new way to reasonably describe the negative transport phenomena appearing in asymmetric turbulent flows.
