Experimental Simulation on Aerodynamic Character of D-Shaped Iced Conductor

2012 ◽  
Vol 614-615 ◽  
pp. 1405-1409
Author(s):  
Xin Min Li ◽  
Kuan Jun Zhu ◽  
Bin Liu
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Transmission Line ◽  
Driving Force ◽  
Experimental Simulation ◽  
Key Factor ◽  
Simulation And Experiment ◽  
And Control

The dynamics force of iced-conductor is the driving force of galloping; its variation is depended on the aerodynamic character of iced conductor. The aerodynamic character of iced conductor is the key factor of galloping of iced-conductor, but the result of theoretically analysis and numerical simulation isn’t suited for the requirement of transmission line project. In the paper, basing on the theoretically analysis and numerical simulation, the simulation tests in wind tunnel of D-shaped iced conductor is stetted up and put into practice under different wind speed and iced thickness, and then the systemic study is carried into execution. The result of research is indicated that there is a better coherence between the numerical simulation and experiment test, and the variation rules of parameters is obvious with the different iced thickness, the result of numerical simulation is the beneficial supplement to the experiment test. The result can not only provide the original date for the galloping analysis, but also validate the affectivity of numerical simulation, support the research of mechanism and control of galloping.

Numerical and Experimental Simulation on Aerodynamic Character of Crescent-Shaped Iced Conductor

2013 ◽  
Vol 275-277 ◽  
pp. 622-627 ◽  
Author(s):  
Xin Min Li ◽  
Kuan Jun Zhu ◽  
Bin Liu
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Transmission Line ◽  
Driving Force ◽  
Experimental Simulation ◽  
Key Factor ◽  
Simulation And Experiment ◽  
And Control

The dynamics force of iced-conductor is the driving force of galloping, its variation is depended on the aerodynamic character of iced conductor. The aerodynamic character of iced conductor is the key factor of galloping of iced-conductor, but the result of theoretically analysis and numerical simulation isn’t suited for the requirement of transmission line project. In the paper, basing on the theoretically analysis and numerical simulation, the simulation tests in wind tunnel of crescent-shaped iced conductor is stetted up and put into practice, and then the systemic study is carried into execution. The result of research is indicated that there is a better coherence between the numerical simulation and experiment test, and the result of numerical simulation is the beneficial supplement to the experiment test. The result can not only provide the original date for the galloping analysis, but also validate the affectivity of numerical simulation, support the research of mechanism and control of galloping.

scholarly journals Numerical Simulation and Wind Tunnel Investigation on Static Characteristics of VAWT Rotor Starter with Lift-Drag Combined Structure

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6167
Author(s):  
Fang Feng ◽  
Guoqiang Tong ◽  
Yunfei Ma ◽  
Yan Li
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Speed Ratio ◽  
Static Characteristics ◽  
Torque Coefficient ◽  
Starting Characteristics ◽  
Static Torque

In order to get rid of the impact of the global financial crisis and actively respond to global climate change, it has become a common choice for global economic development to develop clean energy such as wind energy, improve energy efficiency and reduce greenhouse gas emissions. With the advantages of simple structure, unnecessary facing the wind direction, and unique appearance, the vertical axis wind turbine (VAWT) attracts extensive attention in the field of small and medium wind turbines. The lift-type VAWT exhibits outstanding aerodynamic characteristics at a high tip speed ratio, while the starting characteristics are generally undesirable at a low wind speed; thus, how to improve the starting characteristics of the lift-type VAWT has always been an important issue. In this paper, a lift-drag combined starter (LDCS) suitable for lift-type VAWT was proposed to optimize the starting characteristics of lift-type VAWT. With semi-elliptical drag blades and lift blades equipped on the middle and rear part outside the starter, the structure is characterized by lift-drag combination, weakening the adverse effect of the starter with semi-elliptical drag blades alone on the output performance of the original lift-type VAWT and improving the characteristics of the lift-drag combined VAWT. The static characteristic is one of the important starting characteristics of the wind turbine. The rapid development of computational fluid dynamics has laid a solid material foundation for VAWT. Thus the static characteristics of the LDCS with different numbers of blades were investigated by conducting numerical simulation and wind tunnel tests. The results demonstrated that the static torque coefficient of LDCS increased significantly with the increased incoming wind speed. The average value of the static torque coefficient also increased significantly. This study can provide guidelines for the research of lift-drag combined wind turbines.

scholarly journals Investigation of the Superposition Effect of Oil Vapor Leakage and Diffusion from External Floating-Roof Tanks Using CFD Numerical Simulations and Wind-Tunnel Experiments

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 299
Author(s):  
Jie Fang ◽  
Weiqiu Huang ◽  
Fengyu Huang ◽  
Lipei Fu ◽  
Gao Zhang
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Simulation Method ◽  
Vapor Concentration ◽  
Monitoring And Control ◽  
Wind Tunnel Experiments ◽  
Ambient Wind ◽  
Wind Speeds ◽  
High Concentrations ◽  
And Control

Based on computational fluid dynamics (CFD) and Realizable k-ε turbulence model, we established a numerical simulation method for wind and vapor-concentration fields of various external floating-roof tanks (EFRTs) (single, two, and four) and verified its feasibility using wind-tunnel experiments. Subsequently, we analysed superposition effects of wind speed and concentration fields for different types of EFRTs. The results show that high concentrations of vapor are found near the rim gap of the floating deck and above the floating deck surface. At different ambient wind speeds, interference between tanks is different. When the ambient wind speed is greater than 2 m/s, vapor concentration in leeward area of the rear tank is greater than that between two tanks, which makes it easy to reach explosion limit. It is suggested that more monitoring should be conducted near the bottom area of the rear tank and upper area on the left of the floating deck. Superposition in a downwind direction from the EFRTs becomes more obvious with an increase in the number of EFRTs; vapor superposition occurs behind two leeward tanks after leakage from four large EFRTs. Considering safety, environmental protection, and personnel health, appropriate measures should be taken at these positions for timely monitoring, and control.

scholarly journals Study of Wind Loads and Wind Speed Amplifications on High-Rise Building with Opening by Numerical Simulation and Wind Tunnel Test

2020 ◽  
Vol 2020 ◽  
pp. 1-24
Author(s):  
Fu-Bin Chen ◽  
Xiao-Lu Wang ◽  
Yun Zhao ◽  
Yuan-Bo Li ◽  
Qiu-Sheng Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Pressure ◽  
Wind Loads ◽  
Structural Safety ◽  
Pressure Coefficients ◽  
High Rise ◽  
High Rise Building ◽  
The Mean

High-rise buildings are very sensitive to wind excitations, and wind-induced responses have always been the key factors for structural design. Facade openings have often been used as aerodynamic measures for wind-resistant design of high-rise buildings to meet the requirement of structural safety and comfort. Obvious wind speed amplifications can also be observed inside the openings. Therefore, implementing wind turbines in the openings is of great importance for the utilization of abundant wind energy resources in high-rise buildings and the development of green buildings. Based on numerical simulation and wind tunnel testing, the wind loads and wind speed amplifications on high-rise buildings with openings are investigated in detail. The three-dimensional numerical simulation for wind effects on high-rise building with openings was firstly carried out on FLUENT 15.0 platform by SST k − ε model. The mean wind pressure coefficients and the wind flow characteristics were obtained. The wind speed amplifications at the opening were analyzed, and the distribution law of wind speed in the openings is presented. Meanwhile, a series of wind tunnel tests were conducted to assess the mean and fluctuating wind pressure coefficients in high-rise building models with various opening rates. The variation of wind pressure distribution at typical measuring layers with wind direction was analyzed. Finally, the wind speed amplifications in the openings were studied and verified by the numerical simulation results.

Pressure Characteristics of the Air Flow Field of Cyclone

2013 ◽  
Vol 663 ◽  
pp. 532-536 ◽  
Author(s):  
Chih Hung Huang ◽  
Jia Twu Lee
Keyword(s):  
Fluid Dynamics ◽  
Wind Speed ◽  
Internal Pressure ◽  
Experimental Simulation ◽  
Dust Collector ◽  
Know How ◽  
Key Factor ◽  
Simulation Results ◽  
Fluid Dynamics Equations ◽  
Internal Velocity

The changes in pressure inside the cyclone is a key factor affecting the amount of dust. CFD packages used in this study, with powerful computing features, it's built-in the dynamic fluid dynamics equations, have to know how to self do rational, logical judgments engineering objects. After the attempt of the flow rate and pressure, the experimental simulation results showed: (1) in a fixed wind speed, the vortex rotation was more smoothly, the less amount of fallout; (2) in a fixed wind speed rotating vortex was less smooth, more fallout . (3) the greater the internal pressure, dust kept in the more the amount of air, the less the amount of dust; (4) the internal pressure of the smaller, less dust kept in the air quantity, more fallout. In short, the size of the internal velocity and pressure of the dust collector, was sufficient to affect the important factors of the drop amount of the quantity of dust, and thus determine a dust collector dust of the performance being good or bad.

A Numerical Simulation of Micro Bionic Fish in Vessel

2015 ◽  
Vol 799-800 ◽  
pp. 1083-1087
Author(s):  
Chao Yang ◽  
Fu Xian Zhu ◽  
Jin Yu Zhou ◽  
Ju Fang Chen
Keyword(s):  
Numerical Simulation ◽  
Blood Viscosity ◽  
Driving Force ◽  
Elasticity Modulus ◽  
Fish Tissue ◽  
Alloy Sheet ◽  
Frequency Adjustment ◽  
Giant Magnetostrictive Material ◽  
And Control ◽  
Train Of Thought

The work presented a research method of using the external magnetic field to do a numerical simulation of micro bionic fish. The fishtail skeleton was made of alloy sheet and the fish tissue was stuck on the alloy sheet with giant magnetostrictive material (GMM). Then the mechanical model of bionic fish was established. By controlling the swaying of fishtail through external magnetic frequency adjustment, it is possible to make the fish move about just like a natural fish. The statistics show that the average driving force when the bionic fish is switched on largely depends on the material parameter, blood viscosity and external magnetic frequency. The average driving force will increase with the growing elasticity modulus (EM) of fishtail material and blood viscosity. The bionic fish can get a quite large driving force particularly when the external magnetic frequency is getting close to the natural frequency of the system. Thus, these findings can serve as a major train of thought and gist for the design and control of micro bionic fish in vessel.

scholarly journals Numerical Simulation and Experimental Study on Shaped Charge Warhead of Guided Ammunition

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Guangsong Ma ◽  
Guanglin He
Keyword(s):  
Numerical Simulation ◽  
Cone Angle ◽  
Shaped Charge ◽  
Liner Material ◽  
Penetration Ability ◽  
Simulation And Experiment ◽  
Control Section ◽  
Simulation Results ◽  
And Control ◽  
Shaped Charge Jet

To study the jet penetration capability of shaped charge warhead of guided ammunition, a variable cone angle-shaped charge liner was designed. LS-DYNA software is used to simulate the penetration capability of shaped charge warhead with three different metal materials (copper, steel, and aluminum). Numerical simulation results show that the velocity of the shaped charge jet formed by the three kinds of materials is v aluminum > v copper > v steel , and the residual velocity after penetration is V steel > V aluminum > V copper , the time when the jet starts to break is tcopper > tsteel > taluminum, and the penetration completion time is Tcopper < Taluminum < Tsteel; therefore, according to the numerical simulation results, copper was selected as the liner material, and the principle prototype is made for the experiment. The results of numerical simulation and experiment show that the shaped charge warhead with copper shaped charge liner has good penetration ability and after-effect damage ability to steel target after penetrating the guidance section, steering gear section, and control section.

Research on Vortex-Induced Vibration Behavior of Steel Arch Bridge Hanger

2011 ◽  
Vol 137 ◽  
pp. 429-434 ◽  
Author(s):  
Ling Bai ◽  
Ke Liu
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Vibration Amplitude ◽  
Wind Tunnel Test ◽  
Simulation Technique ◽  
Vortex Induced Vibration ◽  
Arch Bridge ◽  
Vibration Behavior ◽  
Numerical Simulation Technique

A fluid-structure interaction numerical simulation technique based on CFD has been developed to study the vortex-induced vibration behavior of steel arch bridge hanger. Above all, wind acting on bridge hanger is simulated by using Flunet and then vortex-induced dynamic motion of hanger is solved by method in the User Defined Function (UDF). Finally hanger’s transient vibration in wind is achieved by dynamic mesh method provided by Fluent. Using this technique, the vortex-induced vibration behavior of hanger of the Nanjing Dashengguan Yangtze River Bridge is analyzed, including vibration amplitude, vibration-started wind speed and vortex shedding frequency. The study also considers influences of different section type (rectangle, chamfered rectangle and H) of hanger. The following conclusions are obtained. Firstly hanger of different section has different vibration behavior. Secondly vibration-started wind speed of different section hanger differs with each other. Thirdly relation between vibration amplitude and incoming wind speed varies obviously. At the same time, numerical results are compared with those of one wind tunnel test and the out coming is satisfied. Relation between vibration amplitude and wind speed in both numerical simulation and wind tunnel test is similar because vibration-started wind speed in numerical result has only 10% discrepancy with that in wind tunnel test while vibration amplitude’s discrepancy is only 15%. Consequently, analysis results show the reliability of this numerical simulation technique.

scholarly journals A Design and Construction of a Wind Tunnel for Engineering Laboratories

2018 ◽  
Vol 192 ◽  
pp. 02069
Author(s):  
Chalida U-tapao ◽  
Seksun Moryadee
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Test Area ◽  
Maximum Pressure ◽  
Maximum Height ◽  
Wind Speeds ◽  
Air Blower ◽  
And Control ◽  
The Relationship ◽  
Design And Construction

The propose of this research is to demonstrate a design and construction of a wind tunnel for engineering laboratories in order to study the principles and control wind speeds in the wind tunnel. In an experiment in aerodynamics and engineering, we found that diffuser must have a length equal to or more than twice the length of the test in order to prevent the turbulent flow in the test area. The wind speed control system uses Inverter to control a 3-phase frequency of electricity supplied to air blower. In the experiment, the frequency was adjusted in the range from 20.00 to 50.00 Hz. Experiment results show that wind speeds during the test area are in the range of 14.50 to 38.50 meters per second, and the relationship between frequency (Y) and wind speed (X) during the test is linear as follows: Y = (0.7945 × (X-20)) + 14.629. The maximum pressure is 90.31 kilograms per square meter. This wind tunnel can be used to design buildings with a maximum height of 20 meters according to the Bangkok Metropolis Building Control (2001).

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