scholarly journals Wake-induced oscillation behaviour of twin bundle conductor transmission lines

2018 ◽  
Vol 5 (6) ◽  
pp. 180011 ◽  
Author(s):  
Chuan Wu ◽  
Bo Yan ◽  
Guizao Huang ◽  
Bo Zhang ◽  
Zhongbin Lv ◽  
...  
Keyword(s):  
Numerical Method ◽  
Transmission Lines ◽  
Wind Tunnel Test ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Control Technique ◽  
Wind Velocities ◽  
Conductor Line ◽  
Wake Zone ◽  
Lift And Drag

A numerical method to simulate air flow around a bundle conductor line by means of the FLUENT software is presented and verified by a wind tunnel test for aerodynamic characteristics of a twin bundle conductor line. The lift and drag coefficients of the leeward sub-conductor of a twin bundle conductor varying with its relative position in the wake zone to the windward one under different wind velocities are numerically determined by the presented method. A user-defined subroutine of ABAQUS software is developed to apply the aerodynamic loads on each sub-conductor and the electromagnetic force between sub-conductors. The numerical simulation method for wake-induced oscillation of a bundle conductor line is proposed. By means of the numerical method, wake-induced oscillation processes of twin bundle conductor transmission lines under different parameters, including current intensity, spacer layout, span length and wind velocity, are numerically simulated. Moreover, the effects of those parameters on the oscillation characteristics of the lines, such as vibration mode, frequency, amplitude and motion trace, are discussed. The results obtained provide a fundamental basis for the understanding of wake-induced oscillation behaviour of twin bundle conductor transmission lines and the development of control technique for wake-induced oscillation.

Galloping response of sector-shape iced eight bundle conductors

2020 ◽  
Vol 47 (10) ◽  
pp. 1201-1213
Author(s):  
Meng-qi Cai ◽  
Lin-shu Zhou ◽  
Qian Xu ◽  
Xiao-hui Yang ◽  
Xiao-hui Liu
Keyword(s):  
Transmission Lines ◽  
Theoretical Basis ◽  
Wind Tunnel Test ◽  
Dynamic Responses ◽  
Test Results ◽  
The Finite Element Method ◽  
Aerodynamic Coefficients ◽  
Aerodynamic Loads ◽  
Natural Modes ◽  
Wind Velocities

Wind tunnel test results of the aerodynamic coefficients of sector-shape iced eight bundle conductors varying with wind attack angles are presented. Then, by means of the user-defined cable elements, the aerodynamic loads are applied on the cable elements of each sub-conductor through the finite element method (FEM). In addition, the galloping responses of sector-shape iced eight bundle conductors are discussed. Finally, galloping responses, including dynamic responses (natural modes and frequencies), galloping orbits, and amplitudes of typical sector-shape iced eight bundle conductor transmission lines in the cases of different span lengths, wind velocities, and angles of wind attack are studied, respectively. These results provide useful references for a theoretical basis for the study of galloping and the technique of anti-galloping in cold regions.

The Aerodynamic Analysis for Iced Four Bundled Transmission Lines with Typical Crescent

2014 ◽  
Vol 8 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Liu Yuejun ◽  
Tang Ai P. ◽  
Liu Ke T. ◽  
Tu Jie W.
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Transmission Lines ◽  
Angle Of Attack ◽  
Wind Tunnel Test ◽  
Simulation Method ◽  
Single Wire ◽  
Wind Tunnel Tests ◽  
Absolute Value ◽  
Aerodynamic Test

Despite the fact that the wind tunnel tests have been carried out on iced transmission lines subjected to wind load, it is not practical to do wind tunnel tests due to its high cost. This paper describes a detailed numerical simulation method that can be used to instead of wind tunnel tests. Based on the galloping mechanism of iced transmission lines, the aerodynamic test was simulated with the typical crescent super-large thickness iced four bundled conductors. One of the results highlighted in this study is that the wind angle of attack had significant influence on the aerodynamics of iced conductors. The Den-Hartog and O.Nigol coefficient were calculated to determine galloping of iced transmission lines, comparing with the reference of wind tunnel test in the Zhejiang university, the range of the wind angle of attack to the bundled conductor which can lead to gallop is larger than single wire, but the absolute value of amplitude is less than the single conductor, split conductor is more likely to gallop than single conductor.

scholarly journals Wind Tunnel Test Investigation on Unsteady Aerodynamic Coefficients of Iced 4-Bundle Conductors

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Mengqi Cai ◽  
Linshu Zhou ◽  
Hang Lei ◽  
Hanjie Huang
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Critical Parameters ◽  
Torsional Motion ◽  
Aerodynamic Coefficients ◽  
Unsteady Aerodynamic ◽  
Wind Velocities ◽  
Aerodynamic Instability ◽  
Test Investigation

Iced conductor motion is induced by the aerodynamic instability of these conductors. The unsteady aerodynamic characteristics are different from the steady aerodynamic characteristics. The unsteady aerodynamic coefficients of typical iced conductors’ models under torsional motion are measured by the unsteady wind tunnel test. The unsteady aerodynamic coefficients of crescent-shape and sector-shape iced 4-bundle conductors under different torsional motion frequencies, wind velocities, and ice thicknesses are obtained. Wind test results show that there are significant differences between the unsteady and steady aerodynamic coefficients. The unsteady aerodynamic coefficients curve is a loop which is different from the steady aerodynamic coefficients. In addition, the obvious differences exist between unsteady aerodynamic coefficients of crescent-shape and sector-shape iced bundle conductors. Critical parameters, including torsional motion frequencies, wind velocity, ice shape, and ice thickness, have significant influences on unsteady aerodynamic coefficients. It shows that the wind tunnel experiment results are able to provide necessary data for the investigation of iced bundle conductor motion and their prevention techniques.

Research Method of Aerodynamic Characteristics of Heavy Duty Truck in Crosswind

2014 ◽  
Vol 602-605 ◽  
pp. 689-692
Author(s):  
Zhe Zhang ◽  
Lin Lin Ren ◽  
Jie Li
Keyword(s):  
Numerical Simulation ◽  
Comparative Analysis ◽  
Research Method ◽  
Wind Tunnel Test ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Heavy Duty ◽  
Aerodynamic Coefficients ◽  
Heavy Duty Truck ◽  
The Impact

The research program of crosswind aerodynamics was formulated with yaw model test of the relative motion principle for a domestic heavy duty truck. This approach was applied separately wind tunnel test and numerical simulation, to obtain six aerodynamic coefficients of the corresponding heavy duty truck model, and the numerical simulation method was proved to be true by comparative analysis. The conclusions of aerodynamic characteristics got from simulation could provide a useful reference to reduce the impact on crosswind handling stability and the fuel consumption of the heavy duty truck.

Research on the effect of car’s roll motion on the aerodynamic characteristics of high-speed car

2021 ◽  
pp. 095440702110503
Author(s):  
TaiMing Huang ◽  
Yao Yuan ◽  
Hao Pan ◽  
Wei Wang ◽  
Yingying Meng ◽  
...  
Keyword(s):  
High Speed ◽  
Aerodynamic Force ◽  
Wind Tunnel Test ◽  
Safety Evaluation ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Roll Motion ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Numerical Solver

The main purpose of this study is to study the aerodynamic mechanism of periodic roll motion of car body and provide engineering reference for car design and safety evaluation. A simplified roll motion model is established based on a real car model. The two-wheel centerline of the left-wheel symmetrical section is considered as the roll axis, and the overset mesh method was used to model the sinusoidal roll motion of the car. According to the experimental data, the frequency and maximum roll angle were set to be 10 Hz and 2.2°, respectively. A transient numerical solver based on the detached-eddy simulation method is employed. The accuracy of the numerical method is validated by means of the wind tunnel test. Due to the asymmetry of the movement, the aerodynamic change of the roll motion was obvious. It is found that the roll motion is closely related to the aerodynamic characteristics of the car. Because of the hysteresis effect, the phase of aerodynamic force on the car shifts and the most dangerous position of the car is obtained. In addition, the aerodynamic differences of the car parts are found, and the wake is analyzed in detail.

scholarly journals Computational Study Of Curved Underbody Diffusers

2019 ◽  
Vol 128 ◽  
pp. 10002
Author(s):  
Angel Huminic ◽  
Gabriela Huminic
Keyword(s):  
Computational Study ◽  
Aerodynamic Characteristics ◽  
Passenger Car ◽  
Lift And Drag ◽  
Underbody Diffuser ◽  
Ahmed Body

This paper presents new results concerning the aerodynamics of the Ahmed body fitted with a non-flat underbody diffuser. As in previous investigations performed, the angle and the length of the diffuser are the parameters systematically varied within ranges relevant for a hatchback passenger car. Coefficients of lift and drag are compared with the values obtained for the flat underbody diffuser, and the results reveal significant improvements concerning aerodynamic characteristics of body.

Numerical study of geometric morphing wings of the 1303 UCAV

2021 ◽  
pp. 1-17
Author(s):  
B. Nugroho ◽  
J. Brett ◽  
B.T. Bleckly ◽  
R.C. Chin
Keyword(s):  
Flight Control ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Morphing Wing ◽  
Rolling Moment ◽  
Wide Range ◽  
Morphing Wings ◽  
Wing Geometry ◽  
Lift And Drag ◽  
Wing Morphing

ABSTRACT Unmanned Combat Aerial Vehicles (UCAVs) are believed by many to be the future of aerial strike/reconnaissance capability. This belief led to the design of the UCAV 1303 by Boeing Phantom Works and the US Airforce Lab in the late 1990s. Because UCAV 1303 is expected to take on a wide range of mission roles that are risky for human pilots, it needs to be highly adaptable. Geometric morphing can provide such adaptability and allow the UCAV 1303 to optimise its physical feature mid-flight to increase the lift-to-drag ratio, manoeuvrability, cruise distance, flight control, etc. This capability is extremely beneficial since it will enable the UCAV to reconcile conflicting mission requirements (e.g. loiter and dash within the same mission). In this study, we conduct several modifications to the wing geometry of UCAV 1303 via Computational Fluid Dynamics (CFD) to analyse its aerodynamic characteristics produced by a range of different wing geometric morphs. Here we look into two specific geometric morphing wings: linear twists on one of the wings and linear twists at both wings (wash-in and washout). A baseline CFD of the UCAV 1303 without any wing morphing is validated against published wind tunnel data, before proceeding to simulate morphing wing configurations. The results show that geometric morphing wing influences the UCAV-1303 aerodynamic characteristics significantly, improving the coefficient of lift and drag, pitching moment and rolling moment.

scholarly journals Galloping Stability and Wind Tunnel Test of Iced Quad Bundled Conductors considering Wake Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xiaohui Liu ◽  
Ming Zou ◽  
Chuan Wu ◽  
Mengqi Cai ◽  
Guangyun Min ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Transmission Lines ◽  
Degrees Of Freedom ◽  
Wind Tunnel Test ◽  
Aerodynamic Coefficients ◽  
Wake Effect ◽  
Aerodynamic Coefficient ◽  
Set Up ◽  
The Stability ◽  
Three Degrees Of Freedom

A new quad bundle conductor galloping model considering wake effect is proposed to solve the problem of different aerodynamic coefficients of each subconductor of iced quad bundle conductor. Based on the quasistatic theory, a new 3-DOF (three degrees of freedom) galloping model of iced quad bundle conductors is established, which can accurately reflect the energy transfer and galloping of quad bundle conductor in three directions. After a series of formula derivations, the conductor stability judgment formula is obtained. In the wind tunnel test, according to the actual engineering situation, different variables are set up to accurately simulate the galloping of iced quad bundle conductor under the wind, and the aerodynamic coefficient is obtained. Finally, according to the stability judgment formula of this paper, calculate the critical wind speed of conductor galloping through programming. The dates of wind tunnel test and calculation in this paper can be used in the antigalloping design of transmission lines.

Numerical study of the aerodynamic and power characteristics of the cycloidal rotor, under incoming flow

2019 ◽  
pp. 25-34
Author(s):  
Александр Анатольевич Дектерев ◽  
Артем Александрович Дектерев ◽  
Юрий Николаевич Горюнов
Keyword(s):  
Flow Velocity ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Incoming Flow ◽  
Ansys Fluent ◽  
Energy Characteristics ◽  
Power Characteristics ◽  
Calculation Results

Исследование направлено на разработку и апробацию методики численного моделирования аэродинамических и энергетических характеристик циклоидального ротора. За основу взята конфигурация ротора IAT21 L3. Для нее с использованием CFD-пакета ANSYS Fluent построена математическая модель и выполнен расчет. Проанализировано влияние скорости набегающего потока воздуха на движущийся ротор. Математическая модель и полученные результаты исследования могут быть использованы при создании летательных аппаратов с движителями роторного типа. This article addresses the study of the aerodynamic and energy characteristics of a cycloidal rotor subject to the influence of the incoming flow. Cycloidal rotor is one of the perspective devices that provide movement of aircrafts. Despite the fact that the concept of a cycloidal rotor arose in the early twentieth century, the model of a full-scale aircraft has not been yet realized. Foreign scientists have developed models of aircraft ranging in weight from 0.06 to 100 kg. The method of numerical calculation of the cycloidal rotor from the article [1] is considered and realized in this study. The purpose of study was the development and testing of a numerical simulation method for the cycloidal rotor and study aerodynamic and energy characteristics of the rotor in the hovering mode and under the influence of the oncoming flow. The aerodynamic and energy characteristics of the cycloidal rotor, rotating at a speed of 1000 rpm with incoming flow on it with velocities of 20-80 km/h, were calculated. The calculation results showed a directly proportional increase of thrust with an increase of the incoming on the rotor flow velocity, but the power consumed by the rotor was also increased. Increase of the incoming flow velocity leads to the proportional increasing of the lift coefficient and the coefficient of drag. Up to a speed of 80 km/h, an increase in thrust and power is observed; at higher speeds, there is a predominance of nonstationary effects and difficulties in estimating the aerodynamic characteristics of the rotor. In the future, it is planned to consider the 3D formulation of the problem combined with possibility of the flow coming from other sides.

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