For higher accuracy in simulating the transformation of three dimensional waves, in consideration of the advantages of constant panels and linear elements, a combined boundary elements is applied in this research. The...For higher accuracy in simulating the transformation of three dimensional waves, in consideration of the advantages of constant panels and linear elements, a combined boundary elements is applied in this research. The method can be used to remove the transverse vibration due to the accumulation of computational errors. A combined boundary condition of sponge layer and Sommerfeld radiation condition is used to remove the reflected waves from the computing domain. By following the water particle on the water surface, the third order Stokes wave transform is simulated by the numerical wave flume technique. The computed results are in good agreement with theoretical ones.展开更多
A three-step finite element method (FEM) together with Large Eddy Simulation (LES) is applied to incompressible turbulent flow around seabed pipelines at relatively high Reynolds numbers. Both two dimensional and thre...A three-step finite element method (FEM) together with Large Eddy Simulation (LES) is applied to incompressible turbulent flow around seabed pipelines at relatively high Reynolds numbers. Both two dimensional and three-dimensional numerical simulation is carried out to determine the three-dimensional effect. The results of numerical simulation agree quite well with the wave forces acting on pipeline models measured in physical model test.展开更多
It has been shown that Boussinesq type equations, which include the lowest order effects of nonlinearity and frequency dispersion, can provide an accurate description of wave evolution in coastal regions. But differen...It has been shown that Boussinesq type equations, which include the lowest order effects of nonlinearity and frequency dispersion, can provide an accurate description of wave evolution in coastal regions. But different linear dispersion characteristics of the equation can be obtained by different integrating method. In this paper, a new form of the Boussinesq equation is derived by use of two different layer horizontal velocity variables instead of the commonly used depth-averaged velocity or an arbitrary layer velocity. This significantly improves the linear dispersion properties of the Boussinesq equation and enables it to be applied to a wider range of water depth.展开更多
IN recent years more and more attention has been paid to the Devonian of the northern belt of Western Qinling because some large-scale or very large-scale fine-disseminated gold ores have been found. Accordingly, the ...IN recent years more and more attention has been paid to the Devonian of the northern belt of Western Qinling because some large-scale or very large-scale fine-disseminated gold ores have been found. Accordingly, the paleogeographical environments of the Devonian have become a very important project of concern to sedimentologists. Presently there are two kinds of different opinions on the Devonian sedimentary environments. In the first opinon they were consid-展开更多
A nonlinear numerical model has been set up by use of Boussinesq Equation with finite difference method, and has been applied to the simulation of the abnormal change of wave height induced by excavated waterway. Nume...A nonlinear numerical model has been set up by use of Boussinesq Equation with finite difference method, and has been applied to the simulation of the abnormal change of wave height induced by excavated waterway. Numerical results demonstrate that the abnormal change of wave height is due to the adding of the reflected wave height induced by excavated waterway to the incident wave height. Because the angle between the incident wave and the axis of the waterway is smaller than the critical angle, the reflected wave produced by the waterway may propagate to the breakwater and may be added with the incident wave, then the abnormal change of wave height before the breakwater may be caused. So the wave reflection caused by the change of water depth cannot be neglected.展开更多
Aromatic ethers were conveniently brominated with quaternary ammonium bromide and iodosylbenzene in glacial acetic acid under mild conditions to give the corresponding monobromo-aromatic ethers in nearly quantitative ...Aromatic ethers were conveniently brominated with quaternary ammonium bromide and iodosylbenzene in glacial acetic acid under mild conditions to give the corresponding monobromo-aromatic ethers in nearly quantitative yields.展开更多
基金National Natural Science Foundation of China(No.49876026)
文摘For higher accuracy in simulating the transformation of three dimensional waves, in consideration of the advantages of constant panels and linear elements, a combined boundary elements is applied in this research. The method can be used to remove the transverse vibration due to the accumulation of computational errors. A combined boundary condition of sponge layer and Sommerfeld radiation condition is used to remove the reflected waves from the computing domain. By following the water particle on the water surface, the third order Stokes wave transform is simulated by the numerical wave flume technique. The computed results are in good agreement with theoretical ones.
基金Part of results of a project financially supported by the State Key Laboratory of Coastal and Offshore Engineering of Dalian University of Technology
文摘A three-step finite element method (FEM) together with Large Eddy Simulation (LES) is applied to incompressible turbulent flow around seabed pipelines at relatively high Reynolds numbers. Both two dimensional and three-dimensional numerical simulation is carried out to determine the three-dimensional effect. The results of numerical simulation agree quite well with the wave forces acting on pipeline models measured in physical model test.
文摘It has been shown that Boussinesq type equations, which include the lowest order effects of nonlinearity and frequency dispersion, can provide an accurate description of wave evolution in coastal regions. But different linear dispersion characteristics of the equation can be obtained by different integrating method. In this paper, a new form of the Boussinesq equation is derived by use of two different layer horizontal velocity variables instead of the commonly used depth-averaged velocity or an arbitrary layer velocity. This significantly improves the linear dispersion properties of the Boussinesq equation and enables it to be applied to a wider range of water depth.
文摘IN recent years more and more attention has been paid to the Devonian of the northern belt of Western Qinling because some large-scale or very large-scale fine-disseminated gold ores have been found. Accordingly, the paleogeographical environments of the Devonian have become a very important project of concern to sedimentologists. Presently there are two kinds of different opinions on the Devonian sedimentary environments. In the first opinon they were consid-
文摘A nonlinear numerical model has been set up by use of Boussinesq Equation with finite difference method, and has been applied to the simulation of the abnormal change of wave height induced by excavated waterway. Numerical results demonstrate that the abnormal change of wave height is due to the adding of the reflected wave height induced by excavated waterway to the incident wave height. Because the angle between the incident wave and the axis of the waterway is smaller than the critical angle, the reflected wave produced by the waterway may propagate to the breakwater and may be added with the incident wave, then the abnormal change of wave height before the breakwater may be caused. So the wave reflection caused by the change of water depth cannot be neglected.
文摘Aromatic ethers were conveniently brominated with quaternary ammonium bromide and iodosylbenzene in glacial acetic acid under mild conditions to give the corresponding monobromo-aromatic ethers in nearly quantitative yields.
