This paper employs finite element method to solve shallow water equations with absorbing boundary conditions(the third kind,mixed boundary conditions).It is of practical importance in the cases that the land boundarie...This paper employs finite element method to solve shallow water equations with absorbing boundary conditions(the third kind,mixed boundary conditions).It is of practical importance in the cases that the land boundaries of the coastal area are made of porous medium allowing sea water flow in or out.The absorbing boundary conditions are treated as natural boundary conditions in wave equation finite element model.The numerical results for rectangu- lar and quarterly annular harbors indicate that the numerical solutions agree very well with ana- lytic solutions,which are also given in this paper.It is found that the land boundary absorbabili- ty may be significant to long wave oscillations,such as tidal waves in coastal harbors.展开更多
This paper presents analyses and numerical calculations of a single bubble movement and its cavitation behav- ior where the influence of air diffusion,pressure fluctuation,relative velocity between the bubble and flui...This paper presents analyses and numerical calculations of a single bubble movement and its cavitation behav- ior where the influence of air diffusion,pressure fluctuation,relative velocity between the bubble and fluid and the growing bubble burst effect are considered.The calculational resuits provides rather detailed description of a single bubble movement and its cavitation behavior.展开更多
According to the theory of the transport and vorticity dynamics,the paper establishes the theory of vorticity flux and the conservation theorem between the vorticity flux and vortex strength in a plane flow.The theory...According to the theory of the transport and vorticity dynamics,the paper establishes the theory of vorticity flux and the conservation theorem between the vorticity flux and vortex strength in a plane flow.The theory of vorticity flux is a basic one in research on turbulence.展开更多
Using four types of stilling basin models,this paper studies frequency characteris- tics of the fluctuating pressure acting on the stilling basin apron when Froude number is not greater than 4.5.The testing results sh...Using four types of stilling basin models,this paper studies frequency characteris- tics of the fluctuating pressure acting on the stilling basin apron when Froude number is not greater than 4.5.The testing results show that the frequency of fluctuating pressure,f_s in the ranges of 0. 4Hz≤f_s≤1.1Hz.0.2Hz≤f_s≤2.5Hz and 0.4Hz≤f_s≤3.3Hz.can be used as the design frequency corresponding to three patterns of hydraulic jump.The reliability of f_s for three jump patterns is all nearly equal to 90%.展开更多
A eombined finite element and pseudospectral method with a control operator is presented for three-dimension- al vorticity equations.The generalized stability of the scheme is proved and L^2-optimal estimation is obta...A eombined finite element and pseudospectral method with a control operator is presented for three-dimension- al vorticity equations.The generalized stability of the scheme is proved and L^2-optimal estimation is obtained.展开更多
In this paper the structure and scale effect of wall turbulence are investigated.The characteristics of the turbulence structure in the wall region is described.The fact that the turbu- lence in whole flow field is co...In this paper the structure and scale effect of wall turbulence are investigated.The characteristics of the turbulence structure in the wall region is described.The fact that the turbu- lence in whole flow field is controlled mainly by the structure of wall turbulence is demonstrat- ed.Discussion is concentrated on the scale effects of the streak structure,the vortex structure and the bursting frequency.展开更多
文摘This paper employs finite element method to solve shallow water equations with absorbing boundary conditions(the third kind,mixed boundary conditions).It is of practical importance in the cases that the land boundaries of the coastal area are made of porous medium allowing sea water flow in or out.The absorbing boundary conditions are treated as natural boundary conditions in wave equation finite element model.The numerical results for rectangu- lar and quarterly annular harbors indicate that the numerical solutions agree very well with ana- lytic solutions,which are also given in this paper.It is found that the land boundary absorbabili- ty may be significant to long wave oscillations,such as tidal waves in coastal harbors.
文摘This paper presents analyses and numerical calculations of a single bubble movement and its cavitation behav- ior where the influence of air diffusion,pressure fluctuation,relative velocity between the bubble and fluid and the growing bubble burst effect are considered.The calculational resuits provides rather detailed description of a single bubble movement and its cavitation behavior.
文摘According to the theory of the transport and vorticity dynamics,the paper establishes the theory of vorticity flux and the conservation theorem between the vorticity flux and vortex strength in a plane flow.The theory of vorticity flux is a basic one in research on turbulence.
文摘Using four types of stilling basin models,this paper studies frequency characteris- tics of the fluctuating pressure acting on the stilling basin apron when Froude number is not greater than 4.5.The testing results show that the frequency of fluctuating pressure,f_s in the ranges of 0. 4Hz≤f_s≤1.1Hz.0.2Hz≤f_s≤2.5Hz and 0.4Hz≤f_s≤3.3Hz.can be used as the design frequency corresponding to three patterns of hydraulic jump.The reliability of f_s for three jump patterns is all nearly equal to 90%.
文摘A eombined finite element and pseudospectral method with a control operator is presented for three-dimension- al vorticity equations.The generalized stability of the scheme is proved and L^2-optimal estimation is obtained.
文摘In this paper the structure and scale effect of wall turbulence are investigated.The characteristics of the turbulence structure in the wall region is described.The fact that the turbu- lence in whole flow field is controlled mainly by the structure of wall turbulence is demonstrat- ed.Discussion is concentrated on the scale effects of the streak structure,the vortex structure and the bursting frequency.
