Experimental study on the effect of turning angle on drag and lift forces for various cut angles on spheres

2007 ◽  
Vol 221 (3) ◽  
pp. 303-306 ◽  
Author(s):  
A Pudjanarsa
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Experimental Results ◽  
Force Balance ◽  
Turning Angle ◽  
Minimum Value ◽  
Lift Forces ◽  
Drag And Lift

An experimental study on the effect of turning angle on drag and lift forces for various cut angles on spheres is performed. Five different cut angles on different spheres were applied including: 30°, 45°, 53°, 55°, and 75°. Drag and lift forces were measured using a wind tunnel force balance and the wind speed was set so that a corresponding Reynolds number of 5.3 × 104 was achieved. Wind turning angle was varied from 0° to 60°. Experimental results show that, in general, drag and lift forces increase as the turning angle increases. At 0° turning angle, Cd minimum is attained at a cut angle of 53° and is ∼32 per cent less than Cd without cut angle. The maximum C1 is attained at a cut angle of 75° for a turning angle of 50° for approximately 0.68. This value of C1,max is about 855 per cent higher than that of the same turning angle for a cut angle of 30°. At a particular turning angle, lift attains a maximum and beyond that turning angle-drag and lift forces decrease. Minimum value of drag and lift forces reached at the cut angle of 30° for all turning angles.

Experimental Study on the Effect of Reynolds Number Variation on Drag Force for Various Cut Angle on D-Type Cylinders

2014 ◽  
Vol 493 ◽  
pp. 140-144
Author(s):  
Astu Pudjanarsa ◽  
Ardian Ardawalika
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Drag Force ◽  
Free Stream ◽  
Force Balance ◽  
Stream Velocity ◽  
Turning Angle ◽  
Subsonic Wind Tunnel ◽  
Minimum Drag ◽  
Number Variation

Experimental study on the effect of Reynolds number variation on drag force for various cut angles on D-type cylinders was performed. Five different cut angles on different cylinders were applied including: 35o, 45o, 53o, 60o, and 65o. The free stream velocity was varied so the Reynolds number also varied.The experiment was carried out at a subsonic wind tunnel. Drag force for a cut D-type cylinder (for example 35o) was measured using a force balance and wind speed was varied so that corresponding Reynolds number of 2.4×104÷5.3×104 were achieved. Wind turning angle was kept at 0o (without turning angle). This experiment repeated for other D-type cylinders.Experiment results show that, for all D-type cylinders, drag force decreased as the Reynolds number increased, then it was increased after attain minimum drag force. For all D-type cylinders and all variations of Reynolds number the drag minimum is attained at cut angle of 53o. This value is appropriate with previous experiment results.

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.

Computational Fluid Dynamics and Particle Image Velocimetry Supported Examination of Bidirectional Velocity Probes for Measurements in Flames

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
Nadir Yilmaz ◽  
Brian C. Hogan ◽  
Humberto Bocanegra ◽  
A. Burl Donaldson ◽  
Walt Gill
Keyword(s):  
Fluid Dynamics ◽  
Experimental Study ◽  
Reynolds Number ◽  
Wind Tunnel ◽  
Pressure Difference ◽  
Particle Image ◽  
Amplification Factor ◽  
Local Velocity ◽  
Bernoulli’S Equation ◽  
Image Velocimetry

The bidirectional velocity probe has been used in various flames to measure local velocity. The device is based on the pressure difference between a closed forward facing cavity and a closed rearward facing cavity. The probes have been noted to indicate a pressure difference greater than that which would be predicted based on Bernoulli's equation. Each device must be experimentally calibrated in a wind tunnel at similar Reynolds number to determine its “amplification factor.” This study uses PIV, flow visualization and CFD to examine the flow field around the probe, as well as an experimental study which compares various probe configurations for measurement of velocity by pressure differential. The conclusion is that the amplification factor is indeed greater than unity but use of the wind tunnel for calibration is questionable.

Aerodynamic Characteristics of a Deformable Membrane Aerofoil

2014 ◽  
Vol 553 ◽  
pp. 255-260
Author(s):  
Viktor Šajn ◽  
Igor Petrović ◽  
Franc Kosel
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Wind Tunnel ◽  
Lift Coefficient ◽  
Fluid Structure Interaction ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Relative Difference ◽  
Structure Interaction ◽  
Deformable Membrane

In the paper, numerical and experimental study of low Reynolds number airflow around the deformable membrane airfoil (DMA) is presented. Simulations of a fluid-structure interaction between the fluid and the DMA were performed. In the experiment, the DMA model was made from a thin PVC sheet, which was wrapped around the steel rod at the leading and trailing edge. Measurements were performed in a wind tunnel at a chord Reynolds number of 85.7·103, over the angle of attack range from 0° to 15° and DMA shortening ratio from 0.025 to 0.150. Simulations were in an agreement with the experiment, since the average relative difference of coefficient of lift was smaller than 7.3%. For the same value of Reynolds number, DMA shows improved lift coefficient Cy= 2.18, compared to standard rigid airfoils.

Wind Tunnel Test on Icing on a Straight Blade for Vertical Axis Wind Turbine

2011 ◽  
Vol 301-303 ◽  
pp. 1735-1739
Author(s):  
Yan Li ◽  
Fang Feng ◽  
Sheng Mao Li ◽  
Wen Qiang Tian ◽  
Kotaro Tagawa
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Force Balance ◽  
Blade Surface ◽  
Vertical Axis Wind Turbine ◽  
Straight Blade ◽  
Drag And Lift Coefficients ◽  
Ice Accretions ◽  
Drag And Lift

Icing on blade surface of the wind turbine set in cold regions is a serious problem. To invest the mechanism of icing and ice accretion on blade surface, wind tunnel tests were carried out on a static straight blade used for the straight-bladed vertical axis wind turbine by using an icing wind tunnel. The icing and ice accretions on blade surface at some typical angles of attack were observed and recorded in a fixed wind speed and steady flow discharge. The mass of ice accretions on the surface of blade were also measured and compared. At the same time, the drag and lift coefficients were tested by a three-component force balance. Based on the test results, the factors affecting the mass and characteristic of ice accretions and the drag and lift coefficients of the straight blade were discussed.

scholarly journals FLOW INDUCED VIBRATION IN SQUARE CYLINDER OF VARIOUS ANGLES OF ATTACK

2022 ◽  
Vol 23 (1) ◽  
pp. 358-369
Author(s):  
Nur Ain Shafiza Ramzi ◽  
Kee Quen Lee ◽  
NUR AMIRA BALQIS MOHD ZAINURI ◽  
HOOI SIANG KANG ◽  
NOR’AZIZI OTHMAN ◽  
...  
Keyword(s):  
Experimental Study ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Engineering ◽  
Kuala Lumpur ◽  
Velocity Range ◽  
Square Cylinder ◽  
Flow Induced Vibration ◽  
Rigid Cylinder ◽  
Square Cylinders

An experimental study was carried out to identify the effect of angle of attack on flow-induced vibration (FIV) of square cylinders. The experiment was conducted at the Aeronautical and Wind Engineering Laboratory (AEROLAB), UTM Kuala Lumpur using a wind tunnel that was free from external wind conditions. A supporting structure was designed and fabricated to conduct this experiment. The importance of this support structure was to enable the rigid cylinder to suspend and vibrate freely upon excitation of wind speed. The results were analysed through the response of amplitude and frequency of the rigid cylinder over a velocity range of 0.5m/s to 4.0m/s. The results showed that for a square cylinder of ?=0°, vortex-induced vibration (VIV) occurred at low reduced velocity (UR) in range of 5 ? UR ? 10 and galloping occurred at higher reduced velocity which started at UR=15. A tranquil zone was found between VIV and galloping in the reduced velocity range of 10 ? UR ? 15. As for ?=22.5° and 45°, only VIV response was found at low reduced velocity in range of 4? UR ? 9. ABSTRAK: Satu kajian eksperimentasi telah dilakukan bagi mengenal pasti pengaruh sudut serangan oleh getaran cetusan-aliran (FIV) dalam silinder persegi. Eksperimen ini dijalankan di Makmal Kejuruteraan Aeronautika dan Angin (AEROLAB), UTM Kuala Lumpur dengan menggunakan terowong angin yang bebas dari pengaruh angin luar. Struktur sokongan telah direka dan difabrikasi bagi tujuan eksperimen ini. Ini penting bagi membolehkan silinder pegun tergantung dan bergetar dengan bebas semasa ujian kelajuan angin. Dapatan kajian dianalisis melalui tindak balas amplitud dan frekuensi silinder pegun pada kadar halaju 0.5m/s sehingga 4.0m/s. Hasil kajian menunjukkan bahawa bagi silinder persegi ? = 0 °, getaran pengaruh-vorteks (VIV) berlaku pada halaju rendah (UR) dalam julat 5 ? UR ? 10 dan getaran lebih teruk telah ketara berlaku pada kadar halaju berkurang iaitu bermula pada UR = 15. Zon tenang dijumpai antara VIV dan getaran teruk pada kadar halaju berkurang 10 ? UR ? 15. Adapun pada ? = 22.5° dan 45°, hanya tindak balas VIV dijumpai pada halaju rendah dalam kadar 4? UR ? 9.

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.

Numerical Investigation of Drag and Lift Forces on a Sedan Car using Computational Fluid Dynamics

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
M.F. Mohamed ◽  
P.L. Madhavan ◽  
E. Manoj ◽  
K. Sivakumar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Numerical Investigation ◽  
High Speed ◽  
The Body ◽  
Sharp Edge ◽  
Wind Tunnel Simulation ◽  
Lift Forces ◽  
Drag And Lift

The purpose of this work is to cut back the drag, lift and aerodynamic in-stability of a sedan car at high speed levels. In early times, the cars accustomed have a flat faces, sharp edge, conjointly had higher mileage and potency. However later because of the emergence of fuel crisis, scientists improved the model of cars with regard to dynamics of the fluid around the body. Thus, it changes the structure of cars with respect to aeromechanics. Simulation of a vehicle had been done using computational fluid dynamics to obtain the coefficient of drag and coefficient of lift. Finally, these coefficients from computational fluid dynamics are compared wind tunnel simulation.

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