Design of Gust Wind Tunnel With Unsteady and Shear Main-Flows

2021 ◽  
Author(s):  
Yu Nishio ◽  
Ryotaro Miyazaki ◽  
Takanobu Ogawa
Keyword(s):  
Wind Tunnel ◽  
Shear Layer ◽  
Velocity Gradient ◽  
Test Section ◽  
Micro Air Vehicles ◽  
Strong Impact ◽  
Velocity Change ◽  
Linear Shear ◽  
Shutter Mechanism ◽  
Air Vehicles

Abstract Micro air vehicles (MAVs) have been developed for many fields. The MAVs usually receive strong impact from a velocity change in time or space, and facilities for aerodynamic experiments of MAVs under a gusty environment have been required. The present study has developed a gust wind tunnel to generate unsteady and non-uniform flows. We developed a small wind tunnel with eight multi-fans and a shutter mechanism at the upstream of the test section. We controlled the outputs of the fans independently and obtained a linear shear layer with an error of 5 percent. The velocity gradient of the shear layer was from 5 to 8 s−1. The shutter mechanisms provided a longitudinal gust with the velocity change from 2 m/s to 10 m/s within 0.3 seconds.

The Effect of Pulsed Injection on Supersonic Shear Layer Mixing in a Scramjet Combustor

2018 ◽  
Vol 35 (3) ◽  
pp. 203-215
Author(s):  
Leslie Smith ◽  
Saeed Farokhi
Keyword(s):  
Wind Tunnel ◽  
Shear Layer ◽  
Test Section ◽  
Pulse Width ◽  
Static Pressure ◽  
Experimental Studies ◽  
Lower Wall ◽  
Supersonic Wind Tunnel ◽  
Scramjet Combustor ◽  
Secondary Injection

Abstract A novel injector has been designed and cold flow injection tests were performed in a modified supersonic wind tunnel. To complement these experimental studies three dimensional STAR-CCM+CFD simulations were developed. The pulse width may be varied, with options of injecting gas for 33 %, 50 % and 66 % of the injection period. The scramjet combustor environment is simulated in a supersonic wind tunnel through a backward facing step for secondary injection purposes and a 157.5 cm (62-inch) long test section. The gas in secondary injection is carbon dioxide and the primary flow is air. The simulations show a coupled interaction between the forcing from injection and the shear layer. Steady state static pressure measurements on the lower wall of the wind tunnel test section agree well with the simulated static pressure along the lower wall. The pulse width strongly impacts shear layer reattachment on the lower wall and varies between 2.4 and 4.3 step heights. Reduction in duty cycle from 66 % to 33 % at 1 kHz caused ~30 % reduction in the shear layer reattachments distance, which points to large scale mixing enhancement.

scholarly journals WIND TUNNEL CALIBRATION, CORRECTIONS AND EXPERIMENTAL VALIDATION FOR FIXED-WING MICRO AIR VEHICLES MEASUREMENTS

Aviation ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 104-113
Author(s):  
Ahmed Aboelezz ◽  
Yunes Elqudsi ◽  
Mostafa Hassanalian ◽  
Ahmed Desoki
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Aspect Ratio ◽  
Low Reynolds Number ◽  
Micro Air Vehicles ◽  
Measured Data ◽  
Published Data ◽  
Low Aspect Ratio ◽  
Low Reynolds ◽  
Air Vehicles

The increase in the number of Unmanned Aerial Vehicles (UAVs) and Micro Air Vehicles (MAVs), which are used in a variety of applications has led to a surge in low Reynolds number aerodynamics research. Flow around fixedwing MAVs has an unusual behavior due to its low aspect ratio and operates at low Reynolds number, which demanded to upgrade the used wind tunnel for this study. This upgrade enables measuring the small aerodynamics forces and moment of fixed-wing MAVs. The wind tunnel used in this work is upgraded with a state of art data acquisition system to deal with the different sensors signals in the wind tunnel. For accurate measurements, the sting balance, angle sensor, and airspeed sensor are calibrated. For validation purposes, an experiment is made on a low aspect ratio flat plate wing at low Reynolds number, and the measured data are corrected and compared with published results. The procedure presented in this paper for the first time gave a detailed and complete guide for upgrading and calibrating old wind tunnel, all the required corrections to correct the measured data was presented, the turbulence level correction new technique presented in this paper could be used to estimate the flow turbulence effect on the measured data and correct the measured data against published data.

1A2-F01 Development of the Stable Flight Experimental System in the Low Speed Wind Tunnel for Biomimetic Micro Air Vehicles

2009 ◽  
Vol 2009 (0) ◽  
pp. _1A2-F01_1-_1A2-F01_4
Author(s):  
Hiroki SHIBATA ◽  
Atsushi KONDO ◽  
Yoshihiro NAGAHUCHI ◽  
Tomohiro YOSHIDA ◽  
Kazumi OGAWA ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Experimental System ◽  
Micro Air Vehicles ◽  
Low Speed ◽  
Low Speed Wind Tunnel ◽  
Air Vehicles

scholarly journals Effect of wind disturbance on the aerodynamic performance of coaxial rotors during hovering

2019 ◽  
Vol 52 (5-6) ◽  
pp. 665-674 ◽  
Author(s):  
Yao Lei ◽  
Rongzhao Lin
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Micro Air Vehicles ◽  
Aerodynamic Performance ◽  
Vertical Wind ◽  
Wind Gust ◽  
Wind Disturbance ◽  
Wind Tunnel Tests ◽  
Coaxial Rotors ◽  
Air Vehicles

The ability to resist the effect of wind disturbance is vital for micro air vehicles. As the most compact rotor configuration for micro air vehicles, coaxial rotors will be the preferred choice for this type of devices. In this paper, the aerodynamic performance of the coaxial rotors considering the wind gust is presented with both experiments and simulations. First, effect of wind disturbances on the micro air vehicles flight was introduced. Then, low-speed wind tunnel tests were performed on a coaxial rotor with a spacing 0.39 R to obtain the performance in both horizontal and vertical wind of 0–5 m/s with the revolutions per minute ranging from 1500 to 2400. Finally, computational fluid dynamics simulations, as a means of visualizing the flow field to compensate the intuition of the experimental data, were applied by using the sliding mesh to capture the detailed interference of flow field with the distributions of streamline and velocity vector. Compared with wind tunnel tests, simulation results were highly consistent with experiments that allow to capture the flow details around the rotor tip effectively. In addition, the aerodynamic performance was deteriorated by vortices moving or deforming around the blade tip. Also, coaxial rotors can effectively resist the wind disturbance in the horizontal direction while the rotor performance was found to be declined in the vertical wind.

Wind Tunnel Testing of Micro Air Vehicles at Low Reynolds Numbers

2004 ◽  
Author(s):  
Roberto Albertani ◽  
Paul Hubner ◽  
Peter Ifju ◽  
Rick Lind ◽  
Jason Jackowski
Keyword(s):  
Wind Tunnel ◽  
Micro Air Vehicles ◽  
Reynolds Numbers ◽  
Wind Tunnel Testing ◽  
Low Reynolds Numbers ◽  
Low Reynolds ◽  
Tunnel Testing ◽  
Air Vehicles

Use of MEMS For Micro Air Vehicles

2000 ◽  
Author(s):  
Bruce Carroll ◽  
Norman Fitz-Coy ◽  
Wel Shyy ◽  
Toshikazu Nishida
Keyword(s):  
Micro Air Vehicles ◽  
Air Vehicles
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