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.

scholarly journals Cable Suspension and Balance System with Low Support Interference and Vibration for Effective Wind Tunnel Tests

2021 ◽  
Author(s):  
Keum-Yong Park ◽  
Yeol-Hun Sung ◽  
Jae-Hung Han
Keyword(s):  
Wind Tunnel ◽  
Vibration Suppression ◽  
Aerodynamic Load ◽  
Test Model ◽  
Wind Tunnel Tests ◽  
Balance System ◽  
Motion Responses ◽  
Vibration Responses ◽  
Aerodynamic Interference ◽  
Support Interference

AbstractA cable-driven model support concept is suggested and implemented in this paper. In this case, it is a cable suspension and balance system (CSBS), which has the advantages of low support interference and reduced vibration responses for effective wind tunnel tests. This system is designed for both model motion control and aerodynamic load measurements. In the CSBS, the required position or the attitude of the test model is realized by eight motors, which adjust the length, velocity, and acceleration of the corresponding cables. Aerodynamic load measurements are accomplished by a cable balance consisting of eight load cells connected to the assigned cables. The motion responses and load measurement outputs were in good agreement with the reference data. The effectiveness of the CSBS against aerodynamic interference and vibration is experimentally demonstrated through comparative tests with a rear sting and a crescent sting support (CSS). The advantages of the CSBS are examined through several wind tunnel tests of a NACA0015 airfoil model. The cable support of the CSBS clearly showed less aerodynamic interference than the rear sting with a CSS, judging from the drag coefficient profile. Additionally, the CSBS showed excellent vibration suppression characteristics at all angles of attack.

Flutter mitigation of a superlong-span suspension bridge with a double-deck truss girder through wind tunnel tests

2020 ◽  
pp. 107754632094615
Author(s):  
Yanguo Sun ◽  
Yongfu Lei ◽  
Ming Li ◽  
Haili Liao ◽  
Mingshui Li
Keyword(s):  
Wind Tunnel ◽  
Damping Ratio ◽  
Suspension Bridge ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Long Span ◽  
Upper Deck ◽  
Torsional Damping ◽  
And Control ◽  
Wind Induced Vibration

As flutter is a very dangerous wind-induced vibration phenomenon, the mitigation and control of flutter are crucial for the design of long-span bridges. In the present study, via a large number of section model wind tunnel tests, the flutter performance of a superlong-span suspension bridge with a double-deck truss girder was studied, and a series of aerodynamic and structural measures were used to mitigate and control its flutter instability. The results show that soft flutter characterized by a lack of an evident divergent point occurred for the double-deck truss girder. Upper central stabilizers on the upper deck, lower stabilizers below the lower deck, and horizontal flaps installed beside the bottoms of the sidewalks are all effective in suppressing flutter for this kind of truss girder. By combining the structural design with aerodynamic optimizations, a redesigned truss girder with widened upper carriers and sidewalks, and double lower stabilizers combined with the inspection vehicle rails is identified as the optimal flutter mitigation scheme. It was also found that the critical flutter wind speed increases with the torsional damping ratio, indicating that the dampers may be efficient in controlling soft flutter characterized by single-degree-of-freedom torsional vibration. This study aims to provide a useful reference and guidance for the flutter design optimization of long-span bridges with double-deck truss girders.

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.

Optimal placement and active vibration control for piezoelectric smart flexible manipulators using modal H2 norm

2018 ◽  
Vol 29 (11) ◽  
pp. 2333-2343 ◽  
Author(s):  
En Lu ◽  
Wei Li ◽  
Xuefeng Yang ◽  
Yuqiao Wang ◽  
Yufei Liu
Keyword(s):  
Vibration Control ◽  
Dynamic Equation ◽  
Vibration Suppression ◽  
Active Vibration Control ◽  
Piezoelectric Actuators ◽  
Flexible Manipulator ◽  
Optimal Placement ◽  
Singular Perturbation Method ◽  
Assumed Mode Method ◽  
Active Vibration

The optimal placement and active vibration control for piezoelectric smart single flexible manipulator are investigated in this study. Based on the assumed mode method and Hamilton’s principle, the dynamic equation of the piezoelectric smart single flexible manipulator is established. Then, the singular perturbation method is adopted and the coupled dynamic equation is decomposed into slow (rigid) and fast (flexible) subsystems. After that, the couple optimal placement criterion of piezoelectric actuators is proposed on the base of modal H2 norm of the fast subsystem and the change rate of natural frequencies. Using an improved particle swarm optimization algorithm, the optimal placement of piezoelectric actuators is realized. Subsequently, in order to verify the validity and feasibility of the presented optimal placement criterion, the composite controller is designed for the active vibration control of the piezoelectric smart single flexible manipulator. Finally, numerical simulations and experiments are presented. The results demonstrate that the piezoelectric smart single flexible manipulator system has a better single modal controllability and observability and has a good result on the vibration suppression using the optimization results of actuators. The proposed optimal placement criterion and method are feasible and effective.

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.

Comparison Research on Aerodynamic Drags and Pressure Coefficients of Reference Car Models in Automotive Wind Tunnel

2014 ◽  
Vol 989-994 ◽  
pp. 2834-2838 ◽  
Author(s):  
Ying Chao Zhang ◽  
Wei Ding ◽  
Zhe Zhang ◽  
Jie Li
Keyword(s):  
Wind Tunnel ◽  
Test Data ◽  
Wind Tunnels ◽  
Actual Situation ◽  
Wind Tunnel Tests ◽  
Reliable Test ◽  
Pressure Coefficients ◽  
Reference Models ◽  
Comparison Research ◽  
Research Show

The aerodynamic drags of different reference car models were investigated to calibrate the performance of the Automotive Wind Tunnel in Jilin University. The two kinds of reference models--MIRA and SAE reference car models were involved in this paper, considering the actual situation of the Automotive Wind Tunnel in Jilin University. The results of the research show that the Automotive Wind Tunnel in Jilin University can meet the demand for automotive wind tunnel tests and it can get the same performances as other wind tunnels have and reliable test data can be obtained in it.

Vibration suppression method of humanoid flexible arm based on model-free predictive control

2021 ◽  
pp. 1-9
Author(s):  
Qinjun Du ◽  
Chuanming Song ◽  
Wei Ding ◽  
Long Zhao ◽  
Yonggang Luo
Keyword(s):  
Predictive Control ◽  
Vibration Suppression ◽  
Model Free ◽  
Flexible Arm ◽  
Suppression Method

scholarly journals Wind-Induced Phenomena in Long-Span Cable-Supported Bridges: A Comparative Review of Wind Tunnel Tests and Computational Fluid Dynamics Modelling

2021 ◽  
Vol 11 (4) ◽  
pp. 1642
Author(s):  
Yuxiang Zhang ◽  
Philip Cardiff ◽  
Jennifer Keenahan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Careful Analysis ◽  
Wind Effects ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Long Span ◽  
Comparative Review ◽  
Dynamics Modelling

Engineers, architects, planners and designers must carefully consider the effects of wind in their work. Due to their slender and flexible nature, long-span bridges can often experience vibrations due to the wind, and so the careful analysis of wind effects is paramount. Traditionally, wind tunnel tests have been the preferred method of conducting bridge wind analysis. In recent times, owing to improved computational power, computational fluid dynamics simulations are coming to the fore as viable means of analysing wind effects on bridges. The focus of this paper is on long-span cable-supported bridges. Wind issues in long-span cable-supported bridges can include flutter, vortex-induced vibrations and rain–wind-induced vibrations. This paper presents a state-of-the-art review of research on the use of wind tunnel tests and computational fluid dynamics modelling of these wind issues on long-span bridges.

Galloping vibration of stay cable installed with a rectangular lamp: Field observations and wind tunnel tests

2021 ◽  
Vol 215 ◽  
pp. 104685
Author(s):  
An Miao ◽  
Li Shouying ◽  
Liu Zhiwen ◽  
Yan Banfu ◽  
Li Longan ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Field Observations ◽  
Stay Cable ◽  
Wind Tunnel Tests
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