Validation of the AeroDyn Subroutines Using NREL Unsteady Aerodynamics Experiment Data

2002 ◽  
Author(s):  
David J. Laino ◽  
A. Craig Hansen ◽  
Jeff E. Minnema
Keyword(s):  
Wind Tunnel ◽  
Test Data ◽  
Complex Dynamics ◽  
Angle Of Attack ◽  
Unsteady Aerodynamics ◽  
Hysteresis Loops ◽  
Structural Vibration ◽  
Detailed Knowledge ◽  
Vibration Modes ◽  
Wind Tunnel Tests

Completion of the full-scale wind tunnel tests of the NREL Unsteady Aerodynamics Experiment (UAE) Phase VI allowed validation of the AeroDyn wind tuxbine aerodynamics software to commence. Detailed knowledge of the inflow to the UAE was the bane of prior attempts to accomplish any in-depth validation in the past. The wind tunnel tests permitted unprecedented control and measurement of inflow to the UAE rotor. The data collected from these UAE tests are currently under investigation as part of an effort to better understand wind turbine rotor aerodynamics in order to improve aero-elastic modeling techniques. Preliminary results from this study using the AeroDyn subroutines are presented, pointing to several avenues toward improvement. Test data indicate that rotational effects cause more static stall delay over a larger portion of the blades than predicted by current methods. Despite the relatively stiff properties of the UAE, vibration modes appear to influence the aerodynamic forces and system loads. AeroDyn adequately predicts dynamic stall hysteresis loops when appropriate steady, 2-D airfoil tables are used. Problems encountered include uncertainties in converting measured inflow angle to angle of attack for the UAE phase VI. Future work is proposed to address this angle of attack problem and to analyze a slightly more complex dynamics model that incorporates some of the structural vibration modes evident in the test data.

scholarly journals A Decoupled Unified Observation Method of Stochastic Multidimensional Vibration for Wind Tunnel Models

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4694
Author(s):  
Mengde Zhou ◽  
Wei Liu ◽  
Qinqin Wang ◽  
Bing Liang ◽  
Linlin Tang ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Vibration Control ◽  
Active Vibration Control ◽  
Inertial Force ◽  
Vibration Monitoring ◽  
Vibration Modes ◽  
Wind Tunnel Tests ◽  
Stochastic Vibration ◽  
Active Vibration ◽  
Observation Method

Active vibration control is the most effective method for stochastic multidimensional vibration in wind tunnel tests, in which vibration monitoring is the core foundation. Vibrations are induced by the disturbances of several complex air flow instabilities under extreme test conditions with high attack angles. Here, a decoupled unified observation method is proposed in order to fully monitor stochastic multidimensional vibration. First, stochastic multidimensional vibration is explained using the Cartesian coordinate system. Then, the multidimensional vibration decoupling of the pitch plane and the yaw plane is realized according to the proposed decoupling design principle of the long cantilever sting. A unified observation method is presented, based on inertial force theory, to observe multidimensional vibration due to acceleration in each decoupling plane. Verification experiments were conducted in lab and a transonic wind tunnel, using an established real-time monitoring system. The results of lab experiments indicate that, in the frequency region of 0–120 Hz, three vibration modes of a selected stochastic vibration can be decoupled and observed through the vibration components in pitch plane and yaw plane. In addition, wind tunnel tests were carried out according to the working conditions (α = −4~10° with γ = 45°) at Ma = 0.6 and Ma = 0.7, respectively. The results show that six vibration modes of two selected stochastic vibrations can be decoupled and observed through the vibration components in pitch plane and yaw plane. The experimental results prove that stochastic vibration can be fully monitored in multiple dimensions through the vibration components in pitch plane and yaw plane using the proposed decoupled unified observation method. Therefore, these results lay the foundation for active vibration control.

The Aerodynamic Analysis for Iced Four Bundled Transmission Lines with Typical Crescent

2014 ◽  
Vol 8 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Liu Yuejun ◽  
Tang Ai P. ◽  
Liu Ke T. ◽  
Tu Jie W.
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Transmission Lines ◽  
Angle Of Attack ◽  
Wind Tunnel Test ◽  
Simulation Method ◽  
Single Wire ◽  
Wind Tunnel Tests ◽  
Absolute Value ◽  
Aerodynamic Test

Despite the fact that the wind tunnel tests have been carried out on iced transmission lines subjected to wind load, it is not practical to do wind tunnel tests due to its high cost. This paper describes a detailed numerical simulation method that can be used to instead of wind tunnel tests. Based on the galloping mechanism of iced transmission lines, the aerodynamic test was simulated with the typical crescent super-large thickness iced four bundled conductors. One of the results highlighted in this study is that the wind angle of attack had significant influence on the aerodynamics of iced conductors. The Den-Hartog and O.Nigol coefficient were calculated to determine galloping of iced transmission lines, comparing with the reference of wind tunnel test in the Zhejiang university, the range of the wind angle of attack to the bundled conductor which can lead to gallop is larger than single wire, but the absolute value of amplitude is less than the single conductor, split conductor is more likely to gallop than single conductor.

STUDY ON AERODYNAMIC PERFORMANCE OF THE BIONIC AIRFOIL BASED ON THE SWALLOW'S WING

2013 ◽  
Vol 13 (06) ◽  
pp. 1340022 ◽  
Author(s):  
WEIJUN TIAN ◽  
FANGYUAN LIU ◽  
QIAN CONG ◽  
YURONG LIU ◽  
LUQUAN REN
Keyword(s):  
Wind Tunnel ◽  
Wind Turbines ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Aerodynamic Performance ◽  
Wind Tunnel Tests ◽  
Small Wind Turbines ◽  
Aerodynamic Performances ◽  
Drag Ratio ◽  
Bionic Airfoil

This paper demonstrates the design of the airfoil of small wind turbines, the bionic airfoil was inspired by the morphology of the swallow's extended wing. The wind tunnel tests on the bionic and standard airfoils NACA4412 were conducted, and the aerodynamic performances of the airfoils were numerically investigated. The results show that the bionic airfoil has better aerodynamic performance, the lift coefficient and lift-drag ratio are larger than those of the NACA4412; with the angle of attack increases, both the bionic and standard airfoils stall, but the stall characteristics of the bionic airfoil are better.

scholarly journals Multidimensional Vibration Suppression Method with Piezoelectric Control for Wind Tunnel Models

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3998 ◽  
Author(s):  
Mengde Zhou ◽  
Wei Liu ◽  
Linlin Tang ◽  
Zhuang Yao ◽  
Zhengquan Wen ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Test Data ◽  
Evaluation Method ◽  
Vibration Suppression ◽  
Damping Ratio ◽  
Piezoelectric Actuators ◽  
Velocity Feedback ◽  
Wind Tunnel Tests ◽  
Assumed Mode Method ◽  
Suppression Method

In wind tunnel tests, the low-frequency and large-amplitude vibration of the cantilever sting result in poor test data in pitch plane and yaw plane, more seriously, even threatens the safety of wind tunnel tests. To ensure the test data quality, a multidimensional vibration suppression method is proposed to withstand the vibration from any direction, which is based on a system with stackable piezoelectric actuators and velocity feedback employing accelerometers. Firstly, the motion equation of the cantilever sting system is obtained by Hamilton’s principle with the assumed mode method. Then, the multidimensional active control mechanism is qualitatively analyzed and a negative velocity feedback control algorithm combined with a root mean square (RMS) evaluation method is introduced to realize active mass and active damping effect, meanwhile, a weight modification method is performed to determine the sequence number of the stacked piezoelectric actuators and the weight of control voltages in real time. Finally, a multidimensional vibration suppression system was established and verification experiments were carried out in lab and a transonic wind tunnel. The results of lab experiments indicate that the damping ratio of the system is improved more than 4.3 times and the spectrum analyses show reductions of more than 23 dB. In addition, wind tunnel test results have shown that for the working conditions (α = −4~10° with γ = 0° or α = −4~10° with γ = 45°) respectively at 0.6 Ma and 0.7 Ma, the remainder vibration is less than 1.53 g, which proves that the multidimensional vibration suppression method has the ability to resist vibration from any direction to ensure the smooth process of wind tunnel tests.

On self-similar behaviour of the hysteresis loops in pitching motions

2004 ◽  
Vol 108 (1086) ◽  
pp. 427-434 ◽  
Author(s):  
M. R. Soltani ◽  
A. R. Davari
Keyword(s):  
Neural Network ◽  
Experimental Data ◽  
Wind Tunnel ◽  
Standard Model ◽  
Hysteresis Loops ◽  
Similarity Parameter ◽  
Pitching Motion ◽  
Wind Tunnel Tests ◽  
Unsteady Aerodynamic ◽  
Self Similar

AbstractA new similarity parameter has been used for analyzing the unsteady aerodynamic behaviour of vehicles undergoing sinusoidal pitching motion. If this parameter is identical for two unsteady manoeuvres with different reduced frequencies and oscillation amplitudes, the corresponding hysteresis loops of the force and moment collapse on each other. To support and verify this, extensive unsteady wind tunnel tests have been conducted on a standard model, which is a well known fighter type configuration. The acquired data were used to train a certain type of neural network, called the Generalised Regression Neural Network (GRNN), to reduce the number of wind tunnel runs. The scheme, once proved to give the correct results for various conditions, was applied to extend the experimental data to other conditions that have not been tested in the tunnel. Both the predicted and acquired tunnel data were used to show the performance of the similarity parameter.

EFFECTS OF HELICOPTER HORIZONTAL TAIL CONFIGURATIONS ON AERODYNAMIC DRAG CHARACTERISTICS

2017 ◽  
Vol 79 (7-4) ◽  
Author(s):  
Iskandar Shah Ishak ◽  
Muhammad Fitri Mougamadou Zabaroulla
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Aerodynamic Drag ◽  
Angle Of Attack ◽  
Aerodynamic Efficiency ◽  
Wind Tunnel Tests ◽  
Tunnel Model ◽  
The Subject ◽  
And Performance ◽  
Selection Of

Experimental aerodynamic investigations remain the subject of interest in rotorcraft community since the flow around the helicopter is dominated by complex aerodynamics and flow interaction phenomena. The objective of this study is to determine the aerodynamic drag characteristics of helicopter horizontal tail by conducting wind tunnel tests. To fulfil the objective, three of the most common helicopter horizontal tail configurations namely Forward Stabilizer, Low-aft Stabilizer and T-tail Stabilizer, were fabricated as a simplified scaled-down wind tunnel model mated with a standard ellipsoidal fuselage. The test wind speed for this experimental work was 30 m/s, determined from Reynolds sweep, which was corresponding to Reynolds number of 2.8 x 105. Wind tunnel tests were performed at variations angle of attack ranging from -15O to 15O with 5O interval. The results tell that at zero yaw and zero pitch angles, Forward Stabilizer contributed the least drag coefficient at 0.277 implying the configuration could be the best for cruising flight segment. Contrarily to T-tail Stabilizer, this configuration contributed the most drag coefficient at 0.303, which was 9% higher than the former. The T-tail Stabilizer was also found to be the most sensitive to the change of angle of attack where the drag was drastically increased up to 131.35% at -15O angle of attack compares to at zero angle of attack. These findings had successfully testified that the type of stabilizer configuration does significantly influencing the aerodynamic drag characteristics of helicopter. Subsequently, the selection of stabilizer must wisely be done to have the best aerodynamic efficiency and performance for the helicopter. 

scholarly journals CFD-Based Wind Field Correction Method for Terrain Wind Tunnel Tests

2021 ◽  
Vol 2083 (3) ◽  
pp. 032083
Author(s):  
Qi Zhou ◽  
Yuxiang Zhu ◽  
Yu Wang ◽  
Jiceng Han
Keyword(s):  
Wind Tunnel ◽  
Test Data ◽  
Wind Field ◽  
Cfd Simulation ◽  
Wind Tunnel Test ◽  
Correction Method ◽  
Measuring Instruments ◽  
Mountainous Area ◽  
Test Results ◽  
Wind Tunnel Tests

Abstract At present, the wind tunnel test results will have certain deviation and distortion when the wind tunnel test is conducted on certain mountainous terrain with complex local terrain and large variation of wind field characteristics due to the accuracy range of the measuring instruments used in wind tunnel test. In order to correct and obtain correct wind tunnel test results, the wind tunnel tests and numerical simulations were conducted on a super-large bridge in the mountainous area of Southwest China, and the wind parameters of the wind field at the bridge site were obtained. The CFD results were compared with the wind tunnel test results to confirm the credibility of the CFD results; a method was proposed to correct the deviated wind tunnel test data based on the CFD simulation results; the deviated wind tunnel test data were corrected and predicted with the above method, and a more satisfactory correction result was obtained.

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