scholarly journals Ring-Force Balance System for Small Wind Tunnels

2015 ◽  
Vol 13 (0) ◽  
pp. 51-60 ◽  
Author(s):  
Akira IWAKAWA ◽  
Takeshi OSUKA ◽  
Tatsuro SHODA ◽  
Akihiro SASOH ◽  
Hiromitsu KAWAZOE
Keyword(s):  
Force Balance ◽  
Wind Tunnels ◽  
Balance System

A novel free floating accelerometer force balance system for shock tunnel applications

Shock Waves ◽  
2005 ◽  
pp. 407-412
Author(s):  
R. Joarder ◽  
D. R. Mahaptra ◽  
G. Jagadeesh
Keyword(s):  
Shock Tunnel ◽  
Force Balance ◽  
Balance System

A Novel Mirror-Image Technique for Wheel and Ground Simulation in Automotive Wind-Tunnels

2005 ◽  
Author(s):  
Satya P. Mavuri ◽  
Simon Watkins ◽  
Jon Watmuff
Keyword(s):  
Mirror Image ◽  
Force Balance ◽  
Wind Tunnels ◽  
Easy Access ◽  
Tunnel Floor ◽  
Balance Accuracy ◽  
Vehicle Aerodynamics ◽  
Image Technique ◽  
Novel Method ◽  
Double Symmetry

A novel method for simulating the relative motions of the wheels and moving ground for road vehicle aerodynamics is presented. The method revisits an old concept where two identical vehicles are used and positioned so that they are mirror images, with the ground being represented by the horizontal plane of symmetry. The method involves double symmetry, where two half models (e.g. a car split down the vertical centerline) contact at the rotating wheel contact patches and the resulting (opened) vehicle halves lie on a reflection plane. This can either be the tunnel floor or the equivalent CFD plane. For some forms of physical testing this offers advantages (such as easy access to wheel cavities and requiring only one vehicle) but sealing the gap between the tunnel floor and the vehicle halves can interfere with the force balance accuracy and problems can arise with time-varying flows crossing the time averaged zero flow boundary. This paper describes the concept and CFD and model-scale EFD evaluations which were found to compare well.

One-Dimension Force Balance System for Hypersonic Vehicle an experimental and Fuzzy Prediction Approach

2018 ◽  
Vol 5 (5) ◽  
pp. 13547-13555 ◽  
Author(s):  
G. Kalaiarassan ◽  
Krishan ◽  
M. Somanadh ◽  
Chandrasegar Thirumalai ◽  
M. Senthil Kumar
Keyword(s):  
Hypersonic Vehicle ◽  
Force Balance ◽  
One Dimension ◽  
Balance System ◽  
Prediction Approach

Driving Force Testing of Lift Mechanism for Green Energy Furniture

2011 ◽  
Vol 201-203 ◽  
pp. 2803-2806
Author(s):  
Tien Li Chen ◽  
Tsing Tshih Tsung ◽  
Liang Yu Yang ◽  
Ho Chang
Keyword(s):  
Driving Force ◽  
Testing Machine ◽  
Green Energy ◽  
Force Balance ◽  
Key Technology ◽  
Balance System ◽  
Universal Testing ◽  
Study Results ◽  
Lift Mechanism ◽  
Key Factor

The purpose of this study is testing the force of green energy lift mechanism and analyzes its result to get the key technology for green energy (saving force and energy). At first, the green energy lift mechanisms on the market are surveyed, then the mechanism are analyzed in this study. The force balance system of the mechanism is used to save force and energy. The position limitation of saving force and energy for the force balance system will be investigated. Universal testing machine is used to test the driving force by the different loads during the lift mechanism moving downward. The tested results of the driving force will be estimated. The study results show that the loads influence significantly the driving force. The angle between pulley and wire is the key factor of the driving force.

scholarly journals Estimation of Aerodynamic Coefficients in a Small Subsonic Wind Tunnel

2018 ◽  
Vol 30 (4) ◽  
pp. 457-463
Author(s):  
Karolina Krajček Nikolić ◽  
Anita Domitrović ◽  
Slobodan Janković
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Internal Force ◽  
Force Balance ◽  
Wind Tunnels ◽  
Subsonic Wind Tunnel ◽  
Lower Reynolds Number ◽  
Scaling Methods ◽  
Reynolds Number Effects ◽  
Wind Tunnel Data

To apply the experimental data measured in a wind tunnel for a scaled aircraft to a free-flying model, conditions of dynamical similarity must be met or scaling procedures introduced. The scaling methods should correct the wind tunnel data regarding model support, wall interference, and lower Reynolds number. To include the necessary corrections, the current scaling techniques use computational fluid dynamics (CFD) in combination with measurements in cryogenic wind tunnels. There are a few methods that enable preliminary calculations of typical corrections considering specific measurement conditions and volume limitation of test section. The purpose of this paper is to present one possible approach to estimating corrections due to sting interference and difference in Reynolds number between the real airplane in cruise regime and its 1:100 model in the small wind tunnel AT-1. The analysis gives results for correction of axial and normal force coefficients. The results of this analysis indicate that the Reynolds number effects and the problem of installation of internal force balance are quite large. Therefore, the wind tunnel AT-1 has limited  usage for aerodynamic coefficient determination of transport airplanes, like Dash 8 Q400 analyzed in this paper.

scholarly journals Virtual Modelling and Testing of the Single and Contra-Rotating Co-Axial Propeller

Drones ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 42
Author(s):  
Balram Panjwani ◽  
Cecile Quinsard ◽  
Dominik Gacia Przemysław ◽  
Jostein Furseth
Keyword(s):  
Experimental Data ◽  
Experimental Testing ◽  
Measurement Data ◽  
Force Balance ◽  
Virtual Model ◽  
Balance System ◽  
Thrust Measurement ◽  
Lift And Drag ◽  
Full Scale Tests ◽  
Thrust And Torque

Propellers are a vital component to achieve successful and reliable operation of drones. However, the drone developer faces many challenges while selecting a propeller and a common approach is to perform static thrust measurement. However, the selection of a propeller using a static thrust measurement system is time-consuming. To overcome a need for the static thrust system a virtual model has been developed for measuring both the static and dynamic thrust of a single and coaxial propeller. The virtual model is reliable enough to minimize the need for full-scale tests. The virtual model has been built using two open-source software Qblade and OpenFoam. Qblade is employed to obtain the lift and drag coefficients of the propeller’s airfoil section. OpenFoam is utilized to perform the flow simulations of propellers and for obtaining the thrust and torque data of the propeller. The developed virtual model is validated with experimental data and the experimental data are obtained by developing a multi-force balance system for measuring thrusts and torques of a single and a pair of coaxial contra-rotating propellers. The data obtained from the propeller virtual model are compared with the measurement data. For a single propeller, the virtual model shows that the estimated forces are close to the experiment at lower rotational speeds. For coaxial propellers, there are some deviations at the rear propeller due to the turbulence and flow disturbance caused by the front propeller. However, the computed thrust data are still accurate enough to be used in selecting the propeller. The studies indicate that in the future, these virtual models will minimize a need for experimental testing.

Performance Evaluation of an Aerodynamic Blade Model Using a Bottom-mounted Force Balance System

2019 ◽  
Author(s):  
C.U. Ebuzeme ◽  
Z.A. Quadri ◽  
Olugbenga Noah ◽  
Emmanuel O. Ogedengbe ◽  
Charles Eguma
Keyword(s):  
Performance Evaluation ◽  
Force Balance ◽  
Balance System ◽  
Blade Model

A new method for force prediction in an accelerometer force balance system using support vector regression

2020 ◽  
Vol 42 (4) ◽  
pp. 880-889
Author(s):  
Sushmita Deka ◽  
Pallekonda Ramesh Babu ◽  
Maneswar Rahang
Keyword(s):  
Support Vector Regression ◽  
Force Measurement ◽  
Aerodynamic Force ◽  
Accurate Prediction ◽  
Force Balance ◽  
Support Vector ◽  
Inference System ◽  
Force Prediction ◽  
Balance System ◽  
Testing Data

The accurate prediction of force is very important in the present scenario of aerodynamic force measurement. The high accuracy of force prediction during calibration facilitates a better accuracy of force measurement in aerodynamic facilities like shock tunnels and wind tunnels. The present study describes the force prediction in an accelerometer force balance system using support vector regression (SVR). The comparison of SVR with the existing force prediction techniques namely, adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) has also been carried out. The accelerometer force balance used in the current experimentation consists of a tri-axial accelerometer to measure the response on an aluminium hemispherical model on the application of force. The impulse forces were applied along the axial, normal and azimuthal directions. The forces were predicted using the accelerations obtained from the tri-axial accelerometer. SVR method was able to predict the forces quite accurately as compared to ANFIS and ANN. However, SVR has the advantage over ANFIS and ANN in that it is independent of the magnitude of the training and testing data. It is capable of an accurate prediction of forces with any magnitude of training and testing data, unlike ANFIS and ANN.

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