In the present paper, a new dynamic subgrid-scale (SGS) model of turbulent stress and heat flux for stratified shear flow is proposed. Based on our calculated results of stratified channel flow, the dynamic subgrid-sc...In the present paper, a new dynamic subgrid-scale (SGS) model of turbulent stress and heat flux for stratified shear flow is proposed. Based on our calculated results of stratified channel flow, the dynamic subgrid-scale model developed in this paper is shown to be effective for large eddy simulation (LES) of stratified turbulent shear flows. The new SGS model is then applied to the LES of the stratified turbulent channel flow to investigate the coupled shear and buoyancy effects on the behavior of turbulent statistics, turbulent heat transfer and flow structures at different Richardson numbers.展开更多
The coupling effects of rib heights and fluid properties on turbulent convective heat transfer of kerosene flow through the rectangular duct on the ribbed bottom wall are studied numerically in this paper.The numerica...The coupling effects of rib heights and fluid properties on turbulent convective heat transfer of kerosene flow through the rectangular duct on the ribbed bottom wall are studied numerically in this paper.The numerical simulation is based on the ten components surrogate model of kerosene and the Reynolds average method combined with the re-normalized group(RNG)k-εturbulence model.The turbulent vortex structures and heat transfer characteristics of kerosene flowing over rectangular ribs of different heights are obtained.The results show that three dimensional vortices are generated by the ribs,and the vortices alter local flow significantly,leading to both enhanced and reduced convective heat transfer at different locations near the ribs.In addition,it is found that with the increase of rib height,the average Nusselt number and the wall friction factor on the ribbed wall also increase.For the present study,the maximum heat transfer enhancement rate of kerosene flow is 72.16%,and the ratio of rib-to-duct height is 0.75.展开更多
基金This work was supported by the National Science Fund for Distinguished Scholars (No.10125210)the National Natural Science Foundation of China (Grant No.19889210)+1 种基金 the China NKBRSF Project (No. 2001CB409600) the Hundred Talents Programme of the Chi
文摘In the present paper, a new dynamic subgrid-scale (SGS) model of turbulent stress and heat flux for stratified shear flow is proposed. Based on our calculated results of stratified channel flow, the dynamic subgrid-scale model developed in this paper is shown to be effective for large eddy simulation (LES) of stratified turbulent shear flows. The new SGS model is then applied to the LES of the stratified turbulent channel flow to investigate the coupled shear and buoyancy effects on the behavior of turbulent statistics, turbulent heat transfer and flow structures at different Richardson numbers.
基金supported by the National Natural Science Foundation of China(Grant Nos.12072351 and 11872367).
文摘The coupling effects of rib heights and fluid properties on turbulent convective heat transfer of kerosene flow through the rectangular duct on the ribbed bottom wall are studied numerically in this paper.The numerical simulation is based on the ten components surrogate model of kerosene and the Reynolds average method combined with the re-normalized group(RNG)k-εturbulence model.The turbulent vortex structures and heat transfer characteristics of kerosene flowing over rectangular ribs of different heights are obtained.The results show that three dimensional vortices are generated by the ribs,and the vortices alter local flow significantly,leading to both enhanced and reduced convective heat transfer at different locations near the ribs.In addition,it is found that with the increase of rib height,the average Nusselt number and the wall friction factor on the ribbed wall also increase.For the present study,the maximum heat transfer enhancement rate of kerosene flow is 72.16%,and the ratio of rib-to-duct height is 0.75.
