The flow field over Hainan Island and the Leizhou Peninsula in summer and winter is discussed with three-dimensional mesoscale model developed in the University of Virginia and using the representative meteorological ...The flow field over Hainan Island and the Leizhou Peninsula in summer and winter is discussed with three-dimensional mesoscale model developed in the University of Virginia and using the representative meteorological data of January and July.Simulation results indicate that the local weather characteristics over the Hainan Island are distinctly influenced by theWuzhi Mountain terrain. The cloudy or rainfall weather over the northeast of the Wuzhi Mountain occurs easily, under proper large-scale conditions of flow, temperature and humidity. while west wind prevails. The overcast or rainfall weather is often induced by strong convection in the afternoon over west of the Hainan Island under easterly prevailing wind.展开更多
Electro hydrodynamic analogue (EHA) method is applied to study the flow fields in the West Lake. It gives out a satisfactory result on water velocities and discharges of the bridge openings.
This paper gives a numerical study on the flow and temperature fields in an induced plasma reactor, which worked in 0.5 ATM with air as a working gas. We employed a two-dimensional mode of an inductively coupled plas...This paper gives a numerical study on the flow and temperature fields in an induced plasma reactor, which worked in 0.5 ATM with air as a working gas. We employed a two-dimensional mode of an inductively coupled plasma to calculate the temperature and flow field of the reactor as well as the generator. The algorithm is based on the solutions of the two-dimensional continuity, momentum, and energy equations in term of vorticity, stream function and enthalpy. An upwind finite-difference scheme was adopted to solve those equations with appropriate boundary conditions. The computed results show that there is a flat region with little parameter change in the reactor, that the diameter of the region is not much larger than that of the generator and that a deep change of parameter exists in the outer side of the region.展开更多
The mean wind-induced interference effects between two high-rise buildings,in which the interfering buildings have different heights,were numerical simulated in the terrain roughness of B and D types by the Reynolds s...The mean wind-induced interference effects between two high-rise buildings,in which the interfering buildings have different heights,were numerical simulated in the terrain roughness of B and D types by the Reynolds stress equation model(RSM)of fluent.The results are in good agreement with those of the wind tunnel test.Influences of the relative arrangement of two buildings,the height of the interfering buildings and the terrain roughness upon the mean interference effects were analyzed,and the space distributions of IFCPs on the principal building under tandem arrangement were studied.The results indicate that the lower interfering buildings can always bring larger interference factors comparing to the higher ones under tandem arrangement except that the height is larger than 1.25h,and the heights' influence on the mean interference effects will increase as the reduced spacing of two buildings.The influence of heights will be little under stagger arrangement.展开更多
The Von-Karman vortex street flow behind a circular cylinder is successfully solved at Re= 100 for incompressible N- S equations in the form of stream function and vorticity. The method adopted here involves ADI - BGE...The Von-Karman vortex street flow behind a circular cylinder is successfully solved at Re= 100 for incompressible N- S equations in the form of stream function and vorticity. The method adopted here involves ADI - BGE schemes, a recent treatment of body boundary conditions and a new acceptable perturbation model. The solutions of the flow field obtained here are better than previous numerical ones and agree with the experimental data closer. Therefore, it can be used to study sound field numerically. The Curie equation is directly and numerically solved to analyze the distribution of sound sources and the characteristics of their radiated sound field at Re= 100 and to compare with the solution from the theory of vortex sound. It is shown that this method is successful.展开更多
When there are several bodies with relative motion in a flow field,such as the flow in the compression system of modern aero-engine,the flow field will have certain special features,one of which is that the time-space...When there are several bodies with relative motion in a flow field,such as the flow in the compression system of modern aero-engine,the flow field will have certain special features,one of which is that the time-space structure of such multi-bodies unsteady vorticity flow field would be either of unsteady natural flow(UNF)pattern or of unsteady cooperative flow(UCF)pattern.If we further examine the aerodynamic design system of aero-engine,there is no mechanism for the unsteady cooperative flow to occur,in other words the flow field must be of the unsteady natural flow type.If certain technical measures can be adopted to transform UNF into UCF,the aerodynamic performances will surely be improved.This is the main task the author and their colleague have been devoted to and the results are reviewed in the present paper with emphases laid on basic ideas,technical approaches and experimental verifications.展开更多
The concentric bluff-body jet burner is widely used in industrial combustion systems.This kind of burner often generates a considerably complex recirculation zone behind the bluff body.As a result, the fuel often rema...The concentric bluff-body jet burner is widely used in industrial combustion systems.This kind of burner often generates a considerably complex recirculation zone behind the bluff body.As a result, the fuel often remains in the recirculation zone,achieving stability of flame.This study investigates, by means of experiments,the variations of the aerodynamics as the fluid is injected into a combustion chamber through a double concentric burner with a bluff-body.The observation and measurement of the aerodynamics in our experiment are conducted under a cold flow.The controlled parameters in our experiment are:variations in the blockage ratio of the center bluff body,the cone angle of the bluff body,and the velocity ratio(U_s/U_p)of the secondary jet and primary jet;the injection of helium bubbles into the primary and secondary jets to observe the recirculation zone behind the bluff body;using Tufts for observing the characteristics of corner recirculation zone in a combustion chamber,measuring the average velocity of each point within the aerodynamics by the 5-hole pitot tube;measuring the distribution of static pressure of the combustion chamber walls with a static pressure tap.展开更多
文摘The flow field over Hainan Island and the Leizhou Peninsula in summer and winter is discussed with three-dimensional mesoscale model developed in the University of Virginia and using the representative meteorological data of January and July.Simulation results indicate that the local weather characteristics over the Hainan Island are distinctly influenced by theWuzhi Mountain terrain. The cloudy or rainfall weather over the northeast of the Wuzhi Mountain occurs easily, under proper large-scale conditions of flow, temperature and humidity. while west wind prevails. The overcast or rainfall weather is often induced by strong convection in the afternoon over west of the Hainan Island under easterly prevailing wind.
文摘Electro hydrodynamic analogue (EHA) method is applied to study the flow fields in the West Lake. It gives out a satisfactory result on water velocities and discharges of the bridge openings.
文摘This paper gives a numerical study on the flow and temperature fields in an induced plasma reactor, which worked in 0.5 ATM with air as a working gas. We employed a two-dimensional mode of an inductively coupled plasma to calculate the temperature and flow field of the reactor as well as the generator. The algorithm is based on the solutions of the two-dimensional continuity, momentum, and energy equations in term of vorticity, stream function and enthalpy. An upwind finite-difference scheme was adopted to solve those equations with appropriate boundary conditions. The computed results show that there is a flat region with little parameter change in the reactor, that the diameter of the region is not much larger than that of the generator and that a deep change of parameter exists in the outer side of the region.
基金the National Natural Science Foundation of China(Grant No.59895410)
文摘The mean wind-induced interference effects between two high-rise buildings,in which the interfering buildings have different heights,were numerical simulated in the terrain roughness of B and D types by the Reynolds stress equation model(RSM)of fluent.The results are in good agreement with those of the wind tunnel test.Influences of the relative arrangement of two buildings,the height of the interfering buildings and the terrain roughness upon the mean interference effects were analyzed,and the space distributions of IFCPs on the principal building under tandem arrangement were studied.The results indicate that the lower interfering buildings can always bring larger interference factors comparing to the higher ones under tandem arrangement except that the height is larger than 1.25h,and the heights' influence on the mean interference effects will increase as the reduced spacing of two buildings.The influence of heights will be little under stagger arrangement.
基金Supported by National Natural Science Foundation of China and National Education CommissionFoundation of China
文摘The Von-Karman vortex street flow behind a circular cylinder is successfully solved at Re= 100 for incompressible N- S equations in the form of stream function and vorticity. The method adopted here involves ADI - BGE schemes, a recent treatment of body boundary conditions and a new acceptable perturbation model. The solutions of the flow field obtained here are better than previous numerical ones and agree with the experimental data closer. Therefore, it can be used to study sound field numerically. The Curie equation is directly and numerically solved to analyze the distribution of sound sources and the characteristics of their radiated sound field at Re= 100 and to compare with the solution from the theory of vortex sound. It is shown that this method is successful.
基金the financial support received from the National Natural Science Foundation of China(Grant no.10902008)for this project.
文摘When there are several bodies with relative motion in a flow field,such as the flow in the compression system of modern aero-engine,the flow field will have certain special features,one of which is that the time-space structure of such multi-bodies unsteady vorticity flow field would be either of unsteady natural flow(UNF)pattern or of unsteady cooperative flow(UCF)pattern.If we further examine the aerodynamic design system of aero-engine,there is no mechanism for the unsteady cooperative flow to occur,in other words the flow field must be of the unsteady natural flow type.If certain technical measures can be adopted to transform UNF into UCF,the aerodynamic performances will surely be improved.This is the main task the author and their colleague have been devoted to and the results are reviewed in the present paper with emphases laid on basic ideas,technical approaches and experimental verifications.
文摘The concentric bluff-body jet burner is widely used in industrial combustion systems.This kind of burner often generates a considerably complex recirculation zone behind the bluff body.As a result, the fuel often remains in the recirculation zone,achieving stability of flame.This study investigates, by means of experiments,the variations of the aerodynamics as the fluid is injected into a combustion chamber through a double concentric burner with a bluff-body.The observation and measurement of the aerodynamics in our experiment are conducted under a cold flow.The controlled parameters in our experiment are:variations in the blockage ratio of the center bluff body,the cone angle of the bluff body,and the velocity ratio(U_s/U_p)of the secondary jet and primary jet;the injection of helium bubbles into the primary and secondary jets to observe the recirculation zone behind the bluff body;using Tufts for observing the characteristics of corner recirculation zone in a combustion chamber,measuring the average velocity of each point within the aerodynamics by the 5-hole pitot tube;measuring the distribution of static pressure of the combustion chamber walls with a static pressure tap.
