The convection structure in a rectangular channel with a horizontal flow forΓ = 12 was studied. The simulations were preformed by solving the hydrodynamic equations using theSIMPLE method. The convective behavior in ...The convection structure in a rectangular channel with a horizontal flow forΓ = 12 was studied. The simulations were preformed by solving the hydrodynamic equations using theSIMPLE method. The convective behavior in an absolutely and convectively unstable regime wasstudied. The results show that the two types of convection patterns in this system appear dependingon the convection intensity and horizontal flow. A periodically localized traveling wave state wasfound in this system.展开更多
A detailed experimental research on characteristics of the hydrodynamicpressure spreading in the base gap of the arch inverted plunge pool was carried out. The features ofthe distributon of its ampitudes and spectral ...A detailed experimental research on characteristics of the hydrodynamicpressure spreading in the base gap of the arch inverted plunge pool was carried out. The features ofthe distributon of its ampitudes and spectral density and its characteristics in time domain fortwo conditions, i. e. , (1) a through gap and (2) a blind gap were given. The influence of the dampat the joint opening upon the hydrodynamic pressure inside the gap was also investigated.Accordingly, the stabilization mechanism of the arch invert plunge pool was worked out.展开更多
This paper presents a numerical method for simulating the 2-D tidal flow andwater quality with the orthogonal curvilinear coordinates. In order to overcome the computationaldifficulties in natural rivers, such as the ...This paper presents a numerical method for simulating the 2-D tidal flow andwater quality with the orthogonal curvilinear coordinates. In order to overcome the computationaldifficulties in natural rivers, such as the complicated boundary figures, the great disparitybetween length and width of computational domain, etc. , orthogonal boundary-filled grid was used.The irregular domain in physical plane was transformed into a rectangular domain in a transformedplane, and the depth-averaged momentum equations and mass equation were given and discretized basedon the alternating direction implicit finite difference scheme in curvilinear coordinates. Theapplication of the presented method was illustrated by an example of analyzing the Yangtze River inthe vicinity of Nanjing city. A fair agreement between the measured data and computed resultsdemonstrates the validity of the developed method.展开更多
This paper presents numerical and experimental results of the flow in the tipclearance region of the guide vane row in hydraulic turbine. The 3-D Navier-Stokes equations wereemployed to model the flow in end clearance...This paper presents numerical and experimental results of the flow in the tipclearance region of the guide vane row in hydraulic turbine. The 3-D Navier-Stokes equations wereemployed to model the flow in end clearance region of guide vane cascade, the Reynolds stressdifferential model was used for turbulence closure, and the body-fitted curvilinear coordinates andthe SIMPLE! algorithm were adopted. The governing equations were discretized with the non-staggeredgrids by means of the finite volume method. Detailed comparison of hydrodynamical characteristics ofguide vane in hydraulic turbine with or without tip gap was made. Special attention was paid to theinfluence of leakage flow on the main flow and to the movement of tip leakage flow in the end guidevane. The position and strength of the roll-vortex on the sides of guide vane in were determined.The numerical solutions agree with the experimental results obtained by particle image ve-locimetry.The results help to clarify the loss, wear and cavi-tation erosion between the guide vane andrings, especially for those used in the Yellow River which has a high sediment content.展开更多
A three-dimensional numerical model was developed to simulate reaerationusing a body-fitted coordinate system. The model was designed to calculate the velocity and oxygenconcentration separately, called, 'no pairi...A three-dimensional numerical model was developed to simulate reaerationusing a body-fitted coordinate system. The model was designed to calculate the velocity and oxygenconcentration separately, called, 'no pairing resolution'. The velocity was calculated by SIMPLECalgorithm in the body-fitted coordinate system. The considerably proposed model was checked by areaeration experiment couducted in an open channel. The computed results agree considerably wellwith the experimental data. The model was also used to predict the reaeration in an S-shapedchannel, and the numerical results are discussed.展开更多
文摘The convection structure in a rectangular channel with a horizontal flow forΓ = 12 was studied. The simulations were preformed by solving the hydrodynamic equations using theSIMPLE method. The convective behavior in an absolutely and convectively unstable regime wasstudied. The results show that the two types of convection patterns in this system appear dependingon the convection intensity and horizontal flow. A periodically localized traveling wave state wasfound in this system.
文摘A detailed experimental research on characteristics of the hydrodynamicpressure spreading in the base gap of the arch inverted plunge pool was carried out. The features ofthe distributon of its ampitudes and spectral density and its characteristics in time domain fortwo conditions, i. e. , (1) a through gap and (2) a blind gap were given. The influence of the dampat the joint opening upon the hydrodynamic pressure inside the gap was also investigated.Accordingly, the stabilization mechanism of the arch invert plunge pool was worked out.
文摘This paper presents a numerical method for simulating the 2-D tidal flow andwater quality with the orthogonal curvilinear coordinates. In order to overcome the computationaldifficulties in natural rivers, such as the complicated boundary figures, the great disparitybetween length and width of computational domain, etc. , orthogonal boundary-filled grid was used.The irregular domain in physical plane was transformed into a rectangular domain in a transformedplane, and the depth-averaged momentum equations and mass equation were given and discretized basedon the alternating direction implicit finite difference scheme in curvilinear coordinates. Theapplication of the presented method was illustrated by an example of analyzing the Yangtze River inthe vicinity of Nanjing city. A fair agreement between the measured data and computed resultsdemonstrates the validity of the developed method.
文摘This paper presents numerical and experimental results of the flow in the tipclearance region of the guide vane row in hydraulic turbine. The 3-D Navier-Stokes equations wereemployed to model the flow in end clearance region of guide vane cascade, the Reynolds stressdifferential model was used for turbulence closure, and the body-fitted curvilinear coordinates andthe SIMPLE! algorithm were adopted. The governing equations were discretized with the non-staggeredgrids by means of the finite volume method. Detailed comparison of hydrodynamical characteristics ofguide vane in hydraulic turbine with or without tip gap was made. Special attention was paid to theinfluence of leakage flow on the main flow and to the movement of tip leakage flow in the end guidevane. The position and strength of the roll-vortex on the sides of guide vane in were determined.The numerical solutions agree with the experimental results obtained by particle image ve-locimetry.The results help to clarify the loss, wear and cavi-tation erosion between the guide vane andrings, especially for those used in the Yellow River which has a high sediment content.
文摘A three-dimensional numerical model was developed to simulate reaerationusing a body-fitted coordinate system. The model was designed to calculate the velocity and oxygenconcentration separately, called, 'no pairing resolution'. The velocity was calculated by SIMPLECalgorithm in the body-fitted coordinate system. The considerably proposed model was checked by areaeration experiment couducted in an open channel. The computed results agree considerably wellwith the experimental data. The model was also used to predict the reaeration in an S-shapedchannel, and the numerical results are discussed.
