LIFT PERFORMANCE OF A CAMBERED WING FOR AERODYNAMIC PERFORMANCE ENHANCEMENT OF THE FLAPPING WING

2015 ◽  
Vol 75 (8) ◽  
Author(s):  
H. Yusoff ◽  
N. Iswadi ◽  
A.H. Zulkifly ◽  
Sh. Mohd Firdaus ◽  
M.Z. Abdullah ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Performance Enhancement ◽  
Wind Tunnel Test ◽  
Micro Air Vehicles ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Open Circuit ◽  
Flapping Wing ◽  
Flapping Flight ◽  
Advance Ratio

Flapping-Wing Micro Air Vehicles (FW-MAVs) are small hand-held flying vehicles that can maneuver in constrained space owing to its lightweight, low aspect ratio and the ability to fly in low Reynolds number environment. In this study, the aerodynamic characteristics such as time-averaged lift of camber wings with different five wind tunnel test models with 6, 9, 12, and 15 percent camber were developed and the results were compared with time-averaged lift of a flat wing in order to assess the effects of camber wing on the aerodynamic performance for flapping flight applications. The experiments were performed in an open circuit wind tunnel with of non-return airflow with a test section of (0.3 x 0.3) m and capable of speeds from 0.5 to 30 m/s. The time-averaged lift as functions of advance ratio of the flapping motions with respect to the incoming flows are measured by using a strain gauge balance and KYOWA PCD-300A sensor interface data acquisition system. It is found that camber would bring significant aerodynamic benefits when the flapping flight is in unsteady state regime, with advance ratio less than 1.0. The aerodynamic benefits of camber are found to decay exponentially with the increasing advance ratio. Cambered wing shows significantly higher lift in comparison to the flat wing.

Effect of Icing Airfoil on Aerodynamic Performance of Horizontal Axis Wind Turbine

2021 ◽  
pp. 1-9
Author(s):  
Pham Huu Hoang ◽  
Takao Maeda ◽  
Yasunari Kamada ◽  
Tetsu Tada ◽  
Hanamura Maito ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Performance Test ◽  
Lift Coefficient ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Horizontal Axis Wind Turbine ◽  
Turbine Performance ◽  
Maximum Value

Abstract In this paper, the aerodynamic characteristics is clarified by the airfoil performance test of the model of icing airfoil in wind tunnel. As a results of wind tunnel test, the lift coefficient of model of icing airfoil becomes lower and the drag coefficient becomes higher than those of clean airfoil. With the use of these results, numerical analysis using aeroelastic code was carried out to clarify the influence of icing airfoil on wind turbine performance. As result of the analysis, the rated power with icing airfoil is obtained at higher wind speed than clean one, and the maximum value of output power is decreased by icing airfoil. Compared to clean airfoil, the amplitude of edgewise moment at blade root is increased, which is mainly caused by the effects of mass of icing on the blade.

scholarly journals Aerodynamic Characteristics Evaluation of a Cable-Stayed Bridge Section with a New-Type Hybrid Fairing

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Hoyeop Lee ◽  
Jiho Moon
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Wind Flow ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Aerodynamic Performances ◽  
New Type ◽  
Test Result

In this study, new-type hybrid faring is suggested to improve the aerodynamic performance of the long-span cable-stayed bridge. The proposed fairing is developed by applying the concept of the multibox section to the normal faring. The proposed faring has void regions inside the faring so that wind passes through the gaps in the faring. As a result, the wind flow is changed and the forces to the bridge section are reduced. The efficiency of the proposed faring was verified by a series of wind tunnel test. From the test result, it can be found that aerodynamic performances, such as drag force and flutter resistance, are enhanced.

Experimental Studies on Aerodynamic Characteristics of Pantograph System According to the Pantograph Cover Configurations for High Speed Train

2011 ◽  
Author(s):  
Yeongbin Lee ◽  
Minho Kwak ◽  
Kyu Hong Kim ◽  
Dong-Ho Lee
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Aerodynamic Force ◽  
Experimental Studies ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Experimental Models ◽  
High Speed Train ◽  
Drag And Lift

In this study, the aerodynamic characteristics of pantograph system according to the pantograph cover configurations for high speed train were investigated by wind tunnel test. Wind tunnel tests were conducted in the velocity range of 20∼70m/s with scaled experimental pantograph models. The experimental models were 1/4 scaled simplified pantograph system which consists of a double upper arm and a single lower arm with a square cylinder shaped panhead. The experimental model of the pantograph cover is also 1/4 scaled and were made as 4 different configurations. It is laid on the ground plate which modeled on the real roof shape of the Korean high speed train. Using a load cell, the aerodynamic force such as a lift and a drag which were acting on pantograph system were measured and the aerodynamic effects according to the various configurations of pantograph covers were investigated. In addition, the total pressure distributions of the wake regions behind the panhead of the pantograph system were measured to investigate the variations of flow pattern. From the experimental test results, we checked that the flow patterns and the aerodynamic characteristics around the pantograph systems are varied as the pantograph cover configurations. In addition, it is also found that pantograph cover induced to decrease the aerodynamic drag and lift forces. Finally, we proposed the aerodynamic improvement of pantograph cover and pantograph system for high speed train.

scholarly journals Aerodynamic study of a suspension bridge deck by CFD simulations, wind tunnel tests and full-scale observations

2021 ◽  
Vol 1201 (1) ◽  
pp. 012007
Author(s):  
I. Kusano ◽  
E. Cheynet ◽  
J. B. Jakobsen ◽  
J. Snæbjörnsson
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Suspension Bridge ◽  
Aerodynamic Characteristics ◽  
Full Scale ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Wide Range

Abstract Assessing the aerodynamic characteristics of long-span bridges is fundamental for their design. Depending on the terrain complexity and local wind conditions, episodes of large angles of attack (AoA) of 15° may be observed. However, such large AoAs ( above 10°) are often overlooked in the design process. This paper studies the aerodynamics properties of a flow around a single-box girder for a wide range of AoAs, from –20° to 20°, using numerical simulations. The simulations are based on a 2D unsteady Reynolds-averaged Navier–Stokes (URANS) approach using the k − ω SST turbulence model with a Reynolds number of 1.6 × 105. Numerically obtained aerodynamic static coefficients were compared to wind tunnel test data. The CFD results were generally in good agreement with the wind tunnel tests, especially for small AoAs and positive AoAs. More discrepancies were observed for large negative AoA, likely due to the limitation of modelling 3D railings with 2D simulations. The simulated velocity deficit downstream of the deck was consistent with the one measured in full-scale using short-range Doppler wind lidar instruments. Finally, the Strouhal number from the CFD simulations were in agreement with the value obtained from the full-scale data.

Study on the Aerodynamic Characteristics and Galloping Instability of Conductors Covered with Sector-Shaped Ice by a Wind Tunnel Test

2020 ◽  
Vol 20 (06) ◽  
pp. 2040016
Author(s):  
Jia-Xiang Li ◽  
Jian Sun ◽  
Ye Ma ◽  
Shu-Hong Wang ◽  
Xing Fu
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Ice Thickness ◽  
Shape Parameters ◽  
Aerodynamic Coefficient ◽  
Wind Tunnel Tests ◽  
And Control

Conductors with sector-shaped ice are susceptible to galloping. To prevent and control galloping, it is necessary to study the conductor aerodynamic characteristics. Wind tunnel tests were performed to study the influence of two shape parameters (ice thickness and ice angle) of a conductor with sector-shaped ice on the aerodynamic characteristics considering the roughness of the surface. In addition, the unstable areas for galloping are discussed according to Den Hartog theory and Nigol theory. The results show that with increasing ice thickness, the aerodynamic coefficient curves fluctuate more strongly, and galloping tends to occur; with increasing ice angle, the unstable area becomes larger according to Nigol theory, and the increasing drag coefficient will suppress the unstable areas according to Den Hartog theory. With the increasing two shape parameters, the most affected ranges of the aerodynamic coefficient curves are 150–180∘.

scholarly journals Horizontal Wind Effect on the Aerodynamic Performance of Coaxial Tri-Rotor MAV

2020 ◽  
Vol 10 (23) ◽  
pp. 8612
Author(s):  
Yao Lei ◽  
Yiqiang Ye ◽  
Zhiyong Chen
Keyword(s):  
Wind Tunnel ◽  
Power Consumption ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Horizontal Wind ◽  
Wind Effect ◽  
Rotor Speed ◽  
Wind Tunnel Experiments ◽  
Air Vehicle ◽  
Power Loading

The coaxial Tri-rotor micro air vehicle (MAV) is composed of three coaxial rotors where the aerodynamic characteristics of is complicated in flight especially when the wind effect is introduced. In this paper, the hovering performance of a full-scale coaxial Tri-rotor MAV is analyzed with both the simulations and wind tunnel experiments. Firstly, the wind effect on the aerodynamic performance of coaxial Tri-rotor MAV is established with different rotor speed (1500–2300 rpm) and horizontal wind (0–4 m/s). Secondly, the thrust and power consumption of coaxial Tri-rotor (L/D = 1.6) were obtained with low-speed wind tunnel experiments. Furthermore, the streamline distribution, pressure distribution, velocity contour and vortex distribution with different horizontal wind conditions are obtained by numerical simulations. Finally, combining the experiment results and simulation results, it is noted that the horizontal wind may accelerate the aerodynamic coupling, which resulting in the greater thrust variation up to 9% of the coaxial Tri-rotor MAV at a lower rotor speed. Moreover, the aerodynamic performance is decreased with more power consumption at higher rotor speed where the wind and the downwash flow are interacted with each other. Compared with no wind flow, the shape of the downwash flow and the deformation of the vortex affect the power loading and figure of metric accordingly.

Rancang Bangun Piranti Lunak Pengelola Parameter Akuisisi Data Terowongan Angin Kecepatan Rendah Indonesia

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Ivransa Zuhdi Pane
Keyword(s):  
Wind Tunnel ◽  
Data Acquisition ◽  
Wind Tunnel Test ◽  
Data Acquisition System ◽  
Aerodynamic Characteristics ◽  
Design And Implementation ◽  
Implementation Stages ◽  
Analysis Design ◽  
Data Acquisition Process ◽  
Existing Data

Data acquisition is an important part of a series of activities in a wind tunnel test and determine the validity of aerodynamic characteristics information of the test object. One of the factors which affect the success of the data acquisition process is the control of the data acquisition parameters prior to the execution of the wind tunnel test. A large number of data acquisition parameters, and the configuration complexities of the data acquisition parameters, which are still managed manually, urged the development of a software which is expected to facilitate the management of these parameters in a way that is friendly to use and integratable into the existing data acquisition system. Engineering of data acquisition parameters management software was then carried out through the analysis, design and implementation stages in an iterated manner, starting with a simple prototype toward the establisment of operational product.

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