The sedimentation of a rectangular particle falling in a two-dimensional channel filled with Newtonian fluid was simulated with finite element arbitrary Lagrangian-Eulerian domain method. The numerical procedure was v...The sedimentation of a rectangular particle falling in a two-dimensional channel filled with Newtonian fluid was simulated with finite element arbitrary Lagrangian-Eulerian domain method. The numerical procedure was validated by comparison of the simulation results with existing numerical work. Morea over, good agreement was obtained between the simulation results and experimental measurements performed in the current study. The equilibrium position, stable orientation and drag coefficient ofa rect- angular particle for different particle Reynolds numbers （Rep） were studied. The results show that there is a critical particle Reynolds number for the preferred orientation of a rectangular particle falling in a Newtonian fluid. When Rep is smaller than the critical value, the particle fails with its long side parallel to gravity; otherwise the particle fails with its long side perpendicular to gravity. The critical particle Reynolds number is a decreasing function of the blockage ratio and aspect ratio. The distributions of pressure and shear stress on rectangular particle surface were analyzed. Moreover, the drag coefficient of the rectangular particle decreases as Rep or the blockage ratio increases; however, it appears to be independent of aspect ratio.展开更多
基金the financial support from the Natural Science Fund Project of Chongqing Committee of Science and Technology(No.CSTC.2006BA3023)
文摘The sedimentation of a rectangular particle falling in a two-dimensional channel filled with Newtonian fluid was simulated with finite element arbitrary Lagrangian-Eulerian domain method. The numerical procedure was validated by comparison of the simulation results with existing numerical work. Morea over, good agreement was obtained between the simulation results and experimental measurements performed in the current study. The equilibrium position, stable orientation and drag coefficient ofa rect- angular particle for different particle Reynolds numbers （Rep） were studied. The results show that there is a critical particle Reynolds number for the preferred orientation of a rectangular particle falling in a Newtonian fluid. When Rep is smaller than the critical value, the particle fails with its long side parallel to gravity; otherwise the particle fails with its long side perpendicular to gravity. The critical particle Reynolds number is a decreasing function of the blockage ratio and aspect ratio. The distributions of pressure and shear stress on rectangular particle surface were analyzed. Moreover, the drag coefficient of the rectangular particle decreases as Rep or the blockage ratio increases; however, it appears to be independent of aspect ratio.
