Hypersonic Free Flight Investigation on Rudder Reflection of Aircraft

In order to study the control effect of the rudder surface of the hypersonic vehicle and the coupling dynamic characteristics of the rudder surface deflection and the flight attitude, a technical platform for the deflection and motion coupling of the aircraft rudder surface was designed. The platform ejection mechanism can launch the model into the wind tunnel flow field according to the preset attitude, and model can free flight without support interference. The innovative design of the model internal rudder partial system can guarantee the model to deflect the rudder surface in the free flight process, simulate the real steering process of the aircraft. By changing spring with different springs, the speed of the rudder surface can be changed. The dual optical path and image acquisition technology can capture the motion picture before and after the deflection of the rudder surface from two angles. After the image is matched by model matching, the six degrees of freedom parameter of the model can be changed with the time curve before and after the deflection of the rudder surface, and the area of the six freedom degree curve of the different state model is compared. In other words, the specific influence of dynamic rudder rotation on the motion of the model is known. The wind tunnel test of the model in the hypersonic wind tunnel of the 500 mm is carried out using this platform. The test results are highly repeatable, and the test platform technology is mature and reliable.

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

Discrete Dynamics in Nature and Society ◽

10.1155/2020/8885648 ◽

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.

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Full-Span Flying Wing Wind Tunnel Test: A Body Freedom Flutter Study

Fluids ◽

10.3390/fluids5010034 ◽

2020 ◽

Vol 5 (1) ◽

pp. 34

Author(s):

Pengtao Shi ◽

Jihai Liu ◽

Yingsong Gu ◽

Zhichun Yang ◽

Pier Marzocca

Keyword(s):

Wind Tunnel ◽

Theoretical Analysis ◽

Mass Balance ◽

Degrees Of Freedom ◽

Wind Tunnel Test ◽

Suspension System ◽

The Body ◽

Structural Dynamic ◽

Flutter Speed ◽

Theoretical Results

Aiming at the experimental test of the body freedom flutter for modern high aspect ratio flexible flying wing, this paper conducts a body freedom flutter wind tunnel test on a full-span flying wing flutter model. The research content is summarized as follows: (1) The full-span finite element model and aeroelastic model of an unmanned aerial vehicle for body freedom flutter wind tunnel test are established, and the structural dynamics and flutter characteristics of this vehicle are obtained through theoretical analysis. (2) Based on the preliminary theoretical analysis results, the design and manufacturing of this vehicle are completed, and the structural dynamic characteristics of the vehicle are identified through ground vibration test. Finally, the theoretical analysis model is updated and the corresponding flutter characteristics are obtained. (3) A novel quasi-free flying suspension system capable of releasing pitch, plunge and yaw degrees of freedom is designed and implemented in the wind tunnel flutter test. The influence of the nose mass balance on the flutter results is explored. The study shows that: (1) The test vehicle can exhibit body freedom flutter at low airspeeds, and the obtained flutter speed and damping characteristics are favorable for conducting the body freedom flutter wind tunnel test. (2) The designed suspension system can effectively release the degrees of freedom of pitch, plunge, and yaw. The flutter speed measured in the wind tunnel test is 9.72 m/s, and the flutter frequency is 2.18 Hz, which agree well with the theoretical results (with flutter speed of 9.49 m/s and flutter frequency of 2.03 Hz). (3) With the increasing of the mass balance at the nose, critical speed of body freedom flutter rises up and the flutter frequency gradually decreases, which also agree well with corresponding theoretical results.

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Investigation of aerodynamics of separator delivery from cavity

International Journal of Modern Physics B ◽

10.1142/s0217979220401049 ◽

2020 ◽

Vol 34 (14n16) ◽

pp. 2040104

Author(s):

Fei Xue ◽

Yuchao Wang ◽

Peng Bai

Keyword(s):

Wind Tunnel ◽

Angular Velocity ◽

New Technology ◽

Wind Tunnel Test ◽

Ejection Velocity ◽

Supersonic Wind Tunnel ◽

Velocity Error ◽

Technical Specifications ◽

Ejection Mechanism ◽

The Moment

The ejection test technology is studied in a sub-transonic supersonic wind tunnel using a single cylinder to provide ejection velocity. The angular velocity adjusting device of ejection mechanism is designed, which can adjust the ejection velocity and angular velocity of the model independently. When the ejection cylinder moves downward, the angular velocity adjusting mechanism works at the same time, so that the model has the preset ejection velocity and angular velocity at the moment of leaving the ejection frame. The ejection velocity error is less than 5%, the angular velocity error is less than 10%, and the repetition rate is more than 95%. The new technology has been verified by wind tunnel tests under complex aerodynamic conditions of sub-transonic supersonic and multi-body interference. All parameters have reached or surpassed the existing technical specifications. It has served for model tests many times and met the needs of wind tunnel test research on ejection of embedded weapons in aircraft.

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The Stability Analysis of the Driving Rod of the Wind Tunnel Test Model Based on Workbench

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.799-800.538 ◽

2015 ◽

Vol 799-800 ◽

pp. 538-542

Author(s):

Zi Yan Shao ◽

Wen Jia Chen ◽

Yong Jin Hu ◽

Guan Jian Li

Keyword(s):

Wind Tunnel ◽

Degrees Of Freedom ◽

Wind Tunnel Test ◽

Future Research ◽

Response Analysis ◽

Test Model ◽

Main Research ◽

Theoretical Support ◽

Harmonic Response Analysis ◽

The Stability

The ANSYS Workbench is used in this paper to analyse a kind of wind tunnel test model support platform with 5 degrees of freedom. The driving rod of the pitch motion is chosen as the main research project. By using static structural analysis, modal analysis and harmonic response analysis, a detailed analysis is made on the stress, deformation and frequency of the driving rod, and provides theoretical support for the future research on the stability of the institution.

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Feasibility investigation of large-scale model suspended by cable-driven parallel robot in hypersonic wind tunnel test

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410016662067 ◽

2016 ◽

Vol 231 (13) ◽

pp. 2375-2383 ◽

Cited By ~ 1

Author(s):

Xiaoguang Wang ◽

Miaojiao Peng ◽

Zhenghong Hu ◽

Yueshi Chen ◽

Qi Lin

Keyword(s):

Wind Tunnel ◽

Large Scale ◽

Cfd Simulation ◽

Aerodynamic Force ◽

Wind Tunnel Test ◽

Special Kind ◽

Parallel Robot ◽

Scale Model ◽

Hypersonic Wind Tunnel ◽

Large Scale Model

Cable-driven parallel robot is a special kind of robot, which is actuated by cables. It is already applied in the low speed wind tunnel to get aerodynamic measurement of aircraft model, and the aircraft pose could be adjusted by changing the cable length. Whether it can be used in hypersonic wind tunnel still needs further discussion. This paper presents the dynamics and aerodynamics analysis of a large-scale model supported by 6-DOF cable-driven parallel robot to investigate the feasibility of this special kind of suspension system in hypersonic wind tunnel. The description of this setup with a X-51A-like model is given, and then based on the system dynamic equations, aerodynamic force and stiffness matrix are derived. In the simulation, properties of dynamics and aerodynamics are mainly concerned. A typical shock tunnel with flow duration of about 100 milliseconds is taken as an example, and results show that the system is stable enough to meet the fundamental static wind tunnel test. From the cable tension variation under impact load and the sensitivity analysis, it is likely accessible to derive the aerodynamic forces. Compared with the sting suspension method, cable-driven parallel robot has the priority of higher inherent frequency and more flexible degrees. The interference to the flow field induced by cables is also preliminarily proved to be small by the CFD simulation, which can be acceptable and corrected. Researches conducted show the feasibility of cable-driven parallel robot’s application in hypersonic wind tunnel.

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Characteristics of Wind Velocity and Temperature Change Near an Escarpment-Shaped Road Embankment

The Scientific World JOURNAL ◽

10.1155/2014/695629 ◽

2014 ◽

Vol 2014 ◽

pp. 1-13 ◽

Cited By ~ 3

Author(s):

Young-Moon Kim ◽

Ki-Pyo You ◽

Jang-Youl You

Keyword(s):

Wind Tunnel ◽

Temperature Change ◽

Wind Velocity ◽

Field Measurement ◽

Wind Tunnel Test ◽

Level Difference ◽

Before And After ◽

Wind Velocities ◽

Large Level ◽

Velocity Changes

Artificial structures such as embankments built during the construction of highways influence the surrounding airflow. Various types of damage can occur due to changes in the wind velocity and temperature around highway embankments. However, no study has accurately measured micrometeorological changes (wind velocity and temperature) due to embankments. This study conducted a wind tunnel test and field measurement to identify changes in wind velocity and temperature before and after the construction of embankments around roads. Changes in wind velocity around an embankment after its construction were found to be influenced by the surrounding wind velocity, wind angle, and the level difference and distance from the embankment. When the level difference from the embankment was large and the distance was up to 3H, the degree of wind velocity declines was found to be large. In changes in reference wind velocities around the embankment, wind velocity increases were not proportional to the rate at which wind velocities declined. The construction of the embankment influenced surrounding temperatures. The degree of temperature change was large in locations with large level differences from the embankment at daybreak and during evening hours when wind velocity changes were small.

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