scholarly journals In-orbit aerodynamic coefficient measurements using SOAR (Satellite for Orbital Aerodynamics Research)

2021 ◽  
Vol 180 ◽  
pp. 85-99
Author(s):  
N.H. Crisp ◽  
P.C.E. Roberts ◽  
S. Livadiotti ◽  
A. Macario Rojas ◽  
V.T.A. Oiko ◽  
...  
Keyword(s):  
Aerodynamic Coefficient

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.

An Optimal Estimation of Aerodynamic Parameters for GPS Guided Missile

2013 ◽  
Vol 325-326 ◽  
pp. 734-737
Author(s):  
Li Yan ◽  
Chen Yang ◽  
Chuan Bing Ding
Keyword(s):  
Optimal Estimation ◽  
Estimation Accuracy ◽  
State Variables ◽  
Aerodynamic Coefficients ◽  
Measurement Equation ◽  
Aerodynamic Coefficient ◽  
Error Sources ◽  
Disturbance Source ◽  
Aerodynamic Parameters ◽  
Source Errors

The disturbance factors in the missile flight are obvious,so the analytical equations of missile longitudinal disturbance of movement is derived . The missile body longitudinal aerodynamic parameters are fitting out with wind tunnel experimental data. The equation of system state takes the aerodynamic coefficient errors interference source and GPS error sources as the state variables, and the system measurement equation adopts GPS pseudo-range measurements. In passive segment, the aerodynamic coefficients disturbing errors sources of th missile longitudinal plane is estimated optimally with extended Kalman filter. The results show that the method accelerate the convergence speed of the disturbance source errors, and improve the estimation accuracy of the perturbation errors.

The prediction of axial aerodynamic coefficient reduction using base bleed

2013 ◽  
Vol 31 (1) ◽  
pp. 24-29 ◽  
Author(s):  
D. Regodić ◽  
A. Jevremović ◽  
D. Jerković
Keyword(s):  
Aerodynamic Coefficient ◽  
Base Bleed ◽  
Coefficient Reduction

scholarly journals Aerodynamics of High-Sided Vehicles on Truss Girder Considering Sheltering Effect by Wind Tunnel Tests

2020 ◽  
Vol 15 (2) ◽  
pp. 66-88
Author(s):  
Jingyu Zhang ◽  
Mingjin Zhang ◽  
Yongle Li ◽  
Xu Huang ◽  
Zhong Zheng
Keyword(s):  
Large Scale ◽  
Sudden Change ◽  
Aerodynamic Characteristics ◽  
Leeward Side ◽  
Aerodynamic Coefficients ◽  
Test Vehicle ◽  
Aerodynamic Coefficient ◽  
Running Safety ◽  
Sheltering Effect ◽  
Bridge Tower

Aerodynamic characteristics of vehicles are directly related to their running safety, especially for the high-sided vehicles. In order to study the aerodynamic characteristics under multiple sheltering conditions, a complex large scale (1:20.4) truss model and three high-sided vehicles including articulated lorry, travelling bus and commercial van models with the same scale were built. The aerodynamic coefficients under various sheltering effects of wind barriers with different heights and porosities, bridge tower and the vehicle on the adjacent lane were measured. According to the results, wind barriers can effectively reduce wind speed behind them, thus decreasing the wind load acting on the vehicle, which causes the decrease of the aerodynamic response of all three vehicles. However, the influence at the leeward side is limited due to installation of central stabilizers. When the vehicle passes through the bridge tower, a sudden change occurs, the aerodynamic coefficients decrease and fluctuate in varying degrees, especially for the commercial van. When the vehicle moves in different lanes behind the bridge tower, the sheltering effect of the tower on the aerodynamic coefficient in Lane 1 is much greater than that in Lane 2. With regard to the interference between two vehicles on the adjacent lanes, the relative windward area between the test vehicle and the interference vehicle greatly affects the aerodynamics of the test vehicle.

Study on the Aerodynamic Characteristics and Galloping Instability of Conductors Covered with Sector-Shaped Ice by a Wind Tunnel Test

2020 ◽  
Vol 20 (06) ◽  
pp. 2040016
Author(s):  
Jia-Xiang Li ◽  
Jian Sun ◽  
Ye Ma ◽  
Shu-Hong Wang ◽  
Xing Fu
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Ice Thickness ◽  
Shape Parameters ◽  
Aerodynamic Coefficient ◽  
Wind Tunnel Tests ◽  
And Control

Conductors with sector-shaped ice are susceptible to galloping. To prevent and control galloping, it is necessary to study the conductor aerodynamic characteristics. Wind tunnel tests were performed to study the influence of two shape parameters (ice thickness and ice angle) of a conductor with sector-shaped ice on the aerodynamic characteristics considering the roughness of the surface. In addition, the unstable areas for galloping are discussed according to Den Hartog theory and Nigol theory. The results show that with increasing ice thickness, the aerodynamic coefficient curves fluctuate more strongly, and galloping tends to occur; with increasing ice angle, the unstable area becomes larger according to Nigol theory, and the increasing drag coefficient will suppress the unstable areas according to Den Hartog theory. With the increasing two shape parameters, the most affected ranges of the aerodynamic coefficient curves are 150–180∘.

scholarly journals Effect of turbulence on aerodynamic coefficient of cylinder

2020 ◽  
Vol 510 ◽  
pp. 052032
Author(s):  
Jianfeng Yao ◽  
Guohui Shen ◽  
Wenjuan Lou
Keyword(s):  
Aerodynamic Coefficient
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