Wind-resistant structural optimization of supertall buildings based on high-frequency force balance wind tunnel experiment

2021 ◽  
Vol 248 ◽  
pp. 113247
Author(s):  
An Xu ◽  
Haidong Lin ◽  
Jiyang Fu ◽  
Weixing Sun
Keyword(s):  
Wind Tunnel ◽  
Structural Optimization ◽  
High Frequency ◽  
Wind Tunnel Experiment ◽  
Force Balance

Aerodynamic interference test of quad tilt rotor aircraft in wind tunnel

2019 ◽  
Vol 233 (15) ◽  
pp. 5553-5566 ◽  
Author(s):  
Kun Chen ◽  
Zhiwei Shi ◽  
Shengxiang Tong ◽  
Yizhang Dong ◽  
Jie Chen
Keyword(s):  
Wind Tunnel ◽  
Reference Value ◽  
Ground Effect ◽  
Open Loop ◽  
Force Balance ◽  
Scale Model ◽  
Operating Condition ◽  
Tilt Rotor ◽  
Interference Test ◽  
Aerodynamic Interference

There is an obvious aerodynamic interference problem that occurs for a quad tilt rotor in near-ground hovering or in the conversion operating condition. This paper presents an aerodynamic interference test of the quad tilt rotor in a wind tunnel. A 1:35 scale model of the quad tilt rotor is used in this test. To substitute for the ground, a moveable platform is designed in a low-speed open-loop wind tunnel to simulate different flight altitudes of the quad tilt rotor in hovering or forward flight. A rod six-component force balance is used to measure the loads on the aircraft, and the flow field below the airframe is captured using particle image velocimetry. The experimental results show that the ground effect is significant when the hover height above the ground is less than the rotor diameter of the quad tilt rotor aircraft, and the maximum upload of the airframe is approximately 12% of the total vertical thrust with the appearance of obvious fountain flow. During the conversion operating condition, the upload of the airframe is reduced compared with that in the hovering state, which is affected by rotor wake and incoming flow. The aerodynamic interference test results of the quad tilt rotor aircraft have important reference value in power system selection, control system design, and carrying capacity improvement with the advantage of ground effect.

scholarly journals A Wind Tunnel Study on the Shape, Oscillation, and Internal Circulation of Large Raindrops with Sizes between 2.5 and 7.5 mm

2009 ◽  
Vol 66 (3) ◽  
pp. 755-765 ◽  
Author(s):  
Miklós Szakáll ◽  
Karoline Diehl ◽  
Subir K. Mitra ◽  
Stephan Borrmann
Keyword(s):  
Wind Tunnel ◽  
Oscillation Frequency ◽  
Force Balance ◽  
Equivalent Diameter ◽  
Drop Diameter ◽  
Detailed Knowledge ◽  
Shape Parameters ◽  
Internal Circulation ◽  
Frequency Method ◽  
Axis Ratio

Abstract Precipitation prediction using weather radars requires detailed knowledge of the shape parameters of raindrops falling at their terminal velocities in air. Because the raindrops undergo oscillation, the most important shape parameters from the radar prediction point of view are the equilibrium drop shape, the time-averaged axis ratio, and the oscillation frequency. These parameters for individual water drops with equivalent diameter from 2.5 to 7.5 mm were investigated in a vertical wind tunnel using high-speed video imaging. A very good agreement was found between the measured and the theoretically determined raindrop shape calculated by a force balance model. A new method was developed to determine the equivalent drop diameter with the help of the oscillation frequency. The drop size determination by means of the frequency method was found to be three times more precise than by volumetric methods. The time-averaged axis ratio was found to be equal to the equilibrium axis ratio in the investigated raindrop size range. The analysis of the oscillation frequency of the raindrops revealed that the drops undergo multimode oscillations and are oscillating in a transverse mode in addition to an axisymmetric oblate–prolate mode. Experiments are included in which the internal circulation associated with drop oscillation was investigated and compared to theory.

Wind Tunnel Experiment of Microjet-based Flow Control on a Multi-Element High-Lift Airfoil

2022 ◽  
Author(s):  
Case P. Van Dam ◽  
Sai B. Mothukuri ◽  
Seyedeh Sheida Hosseini ◽  
Edward White ◽  
Lisa Brown ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Flow Control ◽  
Wind Tunnel Experiment ◽  
High Lift

A wind tunnel experiment to investigate the effect of polyvinyl acetate, biochar, and bentonite on wind erosion control

2018 ◽  
Vol 65 (8) ◽  
pp. 1049-1062 ◽  
Author(s):  
Zanyar Feizi ◽  
Shamsollah Ayoubi ◽  
Mohammad Reza Mosaddeghi ◽  
Ali Asghar Besalatpour ◽  
Mojtaba Zeraatpisheh ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Erosion ◽  
Polyvinyl Acetate ◽  
Erosion Control ◽  
Wind Tunnel Experiment ◽  
Wind Erosion Control

Optimization Calculation of Javelin Throwing Results

2014 ◽  
Vol 716-717 ◽  
pp. 764-766
Author(s):  
Min Jiang ◽  
Ji He Zhou
Keyword(s):  
Mathematical Model ◽  
Wind Tunnel ◽  
Initial Velocity ◽  
Angle Of Attack ◽  
Wind Tunnel Experiment ◽  
Aerodynamic Efficiency ◽  
Optimization Calculation ◽  
Computer Optimization ◽  
Necessary And Sufficient

On the basis of javelin wind tunnel experiment, we established mathematical model of javelin flight to conduct a computer optimization and got the conclusions. When the initial velocity is in the range of 25m/s-30m/s, the best throwing condition is: the throwing angle is 40°, the angle of attack is 11°. The javelin throwing condition is not zero angle of attack was necessary and sufficient for obtained aerodynamic efficiency.

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