scholarly journals PENELITIAN MEKANISME STALL AKIBAT PERKEMBANGAN GELEMBUNG SEPARASI PADA SAYAP NACA 0017 SECARA EKSPERIMEN DI TEROWONGAN ANGIN SUBSONIK

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Agus Aribowo
Keyword(s):  
Reynolds Number ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Tunnel Experiment ◽  
Effect Mechanism ◽  
Subsonic Wind Tunnel

This paper presents the results of investigation the separation buble which growing and burst on aerofoil NACA 0017 with effect mechanism of stall in the subsonic wind tunnel. Experiment have done on wind speed 20 m per s and 30 m per s. The data pecked from the orifice of pressure with interval 2 degree until stall position. The result was separation buble which growing on the airfoil, going to ahead of airfoil together with increasing the Reynolds number. After touching, the flow appeared to separate from the upper airfoil without reattachment.

scholarly journals Determine Aerodynamic Characteristics for FX63-137 Aerofoil by Using Subsonic Wind Tunnel

2014 ◽  
Vol 695 ◽  
pp. 651-654 ◽  
Author(s):  
Magedi Moh M. Saad ◽  
Norzelawati Asmuin
Keyword(s):  
Reynolds Number ◽  
Aluminum Alloy ◽  
Wind Tunnel ◽  
Low Reynolds Number ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Cnc Machine ◽  
Subsonic Wind Tunnel ◽  
Low Reynolds

This paper is primarily concentrated with determining aerodynamic characteristics and choosing the best angle of attack at a maximum lift and low drag for the FX 63-137 aerofoil at a low Reynolds number and a speed of 20m/s and 30m/s, by using subsonic wind tunnel through manufacturing the aerofoil by aluminum alloy using a CNC machine. The proposed methodology is divided into several stages. Firstly, manufacturing the aerofoil using an aluminum alloy. Secondly, the testing process is carried out using subsonic wind tunnel. Thirdly, the results are displayed and compared with results produced from related works, in order to find out the best angle of attack at a maximum lift.

Research on the Aerodynamic Measures Impact on Flutter Stability of Steel Truss Suspension Bridge

2013 ◽  
Vol 791-793 ◽  
pp. 378-381
Author(s):  
Hua Bai ◽  
Sen Hua Huang
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Suspension Bridge ◽  
Wind Tunnel Experiment ◽  
Attack Angle ◽  
Torsional Stiffness ◽  
Critical Wind Speed ◽  
Guide Plate ◽  
Steel Truss ◽  
Better Than

The flutter stability of the steel truss suspension bridge is hard to reach the requirement of the wind resisting stability when lacks the torsional stiffness. This paper discusses the influence of aerodynamic measure combination, such as central stabilizer, air director enclosed anti-collision bar and so on, towards the flutter stability of steel truss through the wind tunnel experiment of the bridge of Liu Jia gorge. The result shows: the effect of using both the upper and lower stabilized plate is better than separated used it. when sectionalized dispose upper stabilized plate, the flutter critical wind speed of attack angle will decrease rapidly. Outlaying the horizontal guide plate is better than internally installed; The flutter stability of different attack angle tend to be balanced by widening the horizontal guide plate. The anti-collision bar can be functionalized as the central stabilizer by heightening and enclosing, and effectively increase the critical wind speed of different attack angles of the high truss suspension bridge.

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 Structural Characteristics of Snow Drifts and Cornices

1985 ◽  
Vol 6 ◽  
pp. 287-288 ◽  
Author(s):  
Renji Naruse ◽  
Hiroshi Nishimura ◽  
Norikazu Maeno
Keyword(s):  
Grain Size ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Mass Balance ◽  
Structural Characteristics ◽  
Wind Tunnel Experiment ◽  
Surface Mass Balance ◽  
Field Observations ◽  
Surface Mass ◽  
Horizontal Step

Sorting effects of snow particles during deposition were studied in field observations of snow cornices and wind-tunnel experiment of snow drifts. Grain size, density and hardness were larger at the upper part (root) of a cornice than at the lower part (scarp). Experiments with the use of a horizontal step in a wind-tunnel revealed the importance of redistribution of snow particles on the formation of drifts: at wind speed of 5 m/s, about 40% of particles fallen onto the surface behind a 0.1-m high step were removed by erosion, rebound and creep. The surface mass balance controlling the growth and shape of a drift are briefly discussed.

scholarly journals Experimental and Numerical Analysis of a Seawall’s Effect on Wind Turbine Performance

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3877 ◽  
Author(s):  
Hyun-Goo Kim ◽  
Wan-Ho Jeon
Keyword(s):  
Numerical Analysis ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Flow Separation ◽  
Wind Farm ◽  
Wind Tunnel Experiment ◽  
Scale Model ◽  
Wind Flow ◽  
Cfd Analysis

For the purposes of this study, a wind tunnel experiment and a numerical analysis during ebb and high tides were conducted to determine the positive and negative effects of wind flow influenced by a seawall structure on the performance of wind turbines installed along a coastal seawall. The comparison of the wind flow field between a wind tunnel experiment performed with a 1/100 scale model and a computational fluid dynamics (CFD) analysis confirmed that the MP k-turbulence model estimated flow separation on the leeside of the seawall the most accurately. The CFD analysis verified that wind speed-up occurred due to the virtual hill effect caused by the seawall’s windward slope and the recirculation zone of its rear face, which created a positive effect by mitigating wind shear while increasing the mean wind speed in the wind turbine’s rotor plane. In contrast, the turbulence effect of flow separation on the seawall’s leeside was limited to the area below the wind turbine rotor, and had no negative effect. The use of the CFD verified with the comparison with the wind tunnel experiment was extended to the full-scale seawall, and the results of the analysis based on the wind turbine Supervisory Control and Data Acquisition (SCADA) data of a wind farm confirmed that the seawall effect was equivalent to a 1.5% increase in power generation as a result of a mitigation of the wind profile.

Study on Wind Load about Rotary Reticulated Shell by the Wind Tunnel Experiment

2014 ◽  
Vol 578-579 ◽  
pp. 177-179
Author(s):  
Zi Hou Yuan ◽  
Yi Chen Yuan ◽  
Wei Sun
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Pressure Distribution ◽  
Experimental Methods ◽  
Wind Load ◽  
Wind Tunnel Experiment ◽  
Wind Pressure ◽  
Model Experiments ◽  
Rigid Model ◽  
Flow Similarity

This paper is to study the wind load of rotary reticulated shell by experimental methods. The article conduct rigid model experiments to reticulated shell, measure wind pressure distribution on shell’top. Similar conditions is to meet production model:geometric similarity,flow similarity , Reynolds number equal. These results can be used as a reference for the new version of the wind load criteria.

scholarly journals Influence of Turbulence Model for Wind Turbine Simulation in Low Reynolds Number

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Masami Suzuki
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Turbulence Model ◽  
Turbulence Models ◽  
Leading Edge ◽  
Wind Tunnel Experiment ◽  
Speed Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Developed Turbulence

In designing a wind turbine, the validation of the mathematical model’s result is normally carried out by comparison with wind tunnel experiment data. However, the Reynolds number of the wind tunnel experiment is low, and the flow does not match fully developed turbulence on the leading edge of a wind turbine blade. Therefore, the transition area from laminar to turbulent flow becomes wide under these conditions, and the separation point is difficult to predict using turbulence models. The prediction precision decreases dramatically when working with tip speed ratios less than the maximum power point. This study carries out a steadiness calculation with turbulence model and an unsteadiness calculation with laminar model for a three-blade horizontal axis wind turbine. The validation of the calculations is performed by comparing with experimental results. The power coefficients calculated without turbulence models are in agreement with the experimental data for a tip speed ratio greater than 5.

Badminton Performance Test of Wind Tunnel

2013 ◽  
Vol 860-863 ◽  
pp. 1517-1520
Author(s):  
Jing Hua Zhang ◽  
Ren Huang Wang ◽  
Hong Wei Yue
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Performance Test ◽  
Test System ◽  
Wind Tunnel Experiment ◽  
Hole Diameter ◽  
Classification Rule ◽  
System Software ◽  
The Impact

The badminton wind tunnel experiment quality classification was influenced by a lot of factors, such as the size of the wind tunnel wind speed Settings, the selection of the wind hole diameter size, Experiment parameter Settings of the test system software used standard and experimental error and so on. Therefore, a factorys wind tunnel experimental facility would be used by this paper, in order to make the quality of badminton, wind tunnel wind speed and wind hole diameter are researched further. Through the experiment testing, and combined with badminton wind tunnel experiment of theory knowledge, get the impact of these factors on the quality of badminton classification rule. Theoretical analysis is the same as the result of experiment, which this conclusion is indicated by the experiment that what we do. So as to choose the right wind tunnel device and system software of the test parameters Settings provide certain reference. Also the Badminton the judgment of the quality grade classification standard was provided the important reference frame by it.

scholarly journals BLOWN SAND ON BEACHES

1982 ◽  
Vol 1 (18) ◽  
pp. 73
Author(s):  
Susumu Kubota ◽  
Kiyoshi Horikawa ◽  
Shintaro Hotta
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Vertical Distribution ◽  
Shear Velocity ◽  
Wind Tunnel Experiment ◽  
Transport Rate ◽  
Sand Transport ◽  
Sand Transport Rate ◽  
Empirical Coefficients ◽  
The Vertical Distribution

The blown sand transport rate and the vertical and shore-normal distributions of the wind speed were measured simultaneously on a windy beach. The sand transport rate was measured with conventional total quantity-type traps and with a large trap in the form of a trench. The vertical distribution of the wind speed was measured using an ultrasonic anemometer array consisting of six meters. The distribution of wind speed at a height of 1 m in a section normal to the shoreline was measured with five ultrasonic anemometers. A logarithmic law for the vertical distribution of the wind speed was satisfied, and the wind speed in the section normal to the shoreline was almost constant. The Kawamura and Bagnold formulae were found to predict well the sand transport rate. The trench trap and conventional traps gave empirical coefficients of 1.5 and 1.0, respectively, for the sand transport rate averaged over a section normal to the shoreline. The lower value determined with the conventional traps (1.0) is attributed to their inefficiency compared with the trench trap. In order to obtain data at high shear velocities, a wind tunnel experiment was carried out. This experiment showed that both the Kawamura and Bagnold formulae were valid in the range between 60 to 300 cm/s in the wind shear velocity. The empirical coefficient in the laboratory experiments was 1.0: the difference between the field result with the trench trap and the wind tunnel experiment is attributed to the fluctuations in natural wind.

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