The two fluid model of stratified turbulent two phase flow in aquatic environment is developed in this paper. The motion of each phase is described by a unified multi fluid model in an Eulerian coordinate system. T...The two fluid model of stratified turbulent two phase flow in aquatic environment is developed in this paper. The motion of each phase is described by a unified multi fluid model in an Eulerian coordinate system. The laws of turbulent transportation for each phase, and the restriction of each other between the two phases are completely simulated. The complex two phase turbulence with strong buoyancy effects is selected to examine numerically. The extensive experimental data obtained in stratified flow are used here. Comparison of the results of numerical simulation with the experimental data is conducted. It has shown that the results of numerical simulation are satisfactory.展开更多
Conventional model tests and centrifuge tests are frequently used to investigate seepage erosion. However, the centrifugal test method may not be efficient according to the results of hydraulic conductivity tests and ...Conventional model tests and centrifuge tests are frequently used to investigate seepage erosion. However, the centrifugal test method may not be efficient according to the results of hydraulic conductivity tests and piping erosion tests. The reason why seepage deformation in model tests may deviate from similarity was first discussed in this work. Then, the similarity criterion for seepage deformation in porous media was improved based on the extended Darcy-Brinkman-Forchheimer equation. Finally, the coupled particle flow code–computational fluid dynamics(PFC-CFD) model at the mesoscopic level was proposed to verify the derived similarity criterion. The proposed model maximizes its potential to simulate seepage erosion via the discrete element method and satisfy the similarity criterion by adjusting particle size. The numerical simulations achieved identical results with the prototype, thus indicating that the PFC-CFD model that satisfies the improved similarity criterion can accurately reproduce the processes of seepage erosion at the mesoscopic level.展开更多
The irregular shape of buildings always tenders an enormous challenge to the designers.The wind velocity at the pedestrian level has a specific approach from a comfortable point of view.This investigation highlighted ...The irregular shape of buildings always tenders an enormous challenge to the designers.The wind velocity at the pedestrian level has a specific approach from a comfortable point of view.This investigation highlighted the characteristic of the pedestrian level wind velocity for distinct types of asymmetrical setback buildings.The passed study explored the pedestrian level effect for the axisymmetric models,while this study is based on the models that have symmetry about a single axis.This study investigates the pedestrian level flow fluctuation of setback models with single and double side setbacks at multiple levels.The double-side double setback buildings are efficient to reduce 28%-30%velocity in front of the building and 68%-70%velocity behind the building.Finally it suggests that the double side double setback building is efficient to maintain the velocity at the pedestrian level,roof level,and backside of the building.The setback building can easily control the frequency of fluctuating velocity at downstream flow for both along and across wind conditions.展开更多
文摘The two fluid model of stratified turbulent two phase flow in aquatic environment is developed in this paper. The motion of each phase is described by a unified multi fluid model in an Eulerian coordinate system. The laws of turbulent transportation for each phase, and the restriction of each other between the two phases are completely simulated. The complex two phase turbulence with strong buoyancy effects is selected to examine numerically. The extensive experimental data obtained in stratified flow are used here. Comparison of the results of numerical simulation with the experimental data is conducted. It has shown that the results of numerical simulation are satisfactory.
基金Project(51309086)supported by the National Natural Science Foundation of ChinaProject(20110094120002)supported by the Ministry Education Foundation of ChinaProjects(2014B04914,2011B07214)supported by the Fundamental Research Funds for the Central Universities,China
文摘Conventional model tests and centrifuge tests are frequently used to investigate seepage erosion. However, the centrifugal test method may not be efficient according to the results of hydraulic conductivity tests and piping erosion tests. The reason why seepage deformation in model tests may deviate from similarity was first discussed in this work. Then, the similarity criterion for seepage deformation in porous media was improved based on the extended Darcy-Brinkman-Forchheimer equation. Finally, the coupled particle flow code–computational fluid dynamics(PFC-CFD) model at the mesoscopic level was proposed to verify the derived similarity criterion. The proposed model maximizes its potential to simulate seepage erosion via the discrete element method and satisfy the similarity criterion by adjusting particle size. The numerical simulations achieved identical results with the prototype, thus indicating that the PFC-CFD model that satisfies the improved similarity criterion can accurately reproduce the processes of seepage erosion at the mesoscopic level.
文摘The irregular shape of buildings always tenders an enormous challenge to the designers.The wind velocity at the pedestrian level has a specific approach from a comfortable point of view.This investigation highlighted the characteristic of the pedestrian level wind velocity for distinct types of asymmetrical setback buildings.The passed study explored the pedestrian level effect for the axisymmetric models,while this study is based on the models that have symmetry about a single axis.This study investigates the pedestrian level flow fluctuation of setback models with single and double side setbacks at multiple levels.The double-side double setback buildings are efficient to reduce 28%-30%velocity in front of the building and 68%-70%velocity behind the building.Finally it suggests that the double side double setback building is efficient to maintain the velocity at the pedestrian level,roof level,and backside of the building.The setback building can easily control the frequency of fluctuating velocity at downstream flow for both along and across wind conditions.
