A Wind Tunnel Study of Airflow through Horticultural Crops: Determination of the Drag Coefficient

2006 ◽  
Vol 93 (4) ◽  
pp. 447-457 ◽  
Author(s):  
F.D. Molina-Aiz ◽  
D.L. Valera ◽  
A.J. Álvarez ◽  
A. Madueño
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Horticultural Crops ◽  
Wind Tunnel Study

scholarly journals A wind-tunnel case study: Increasing road cycling velocity by adopting an aerodynamically improved sprint position

2019 ◽  
pp. 175433711986696
Author(s):  
Timothy Crouch ◽  
Paolo Menaspà ◽  
Nathan Barry ◽  
Nicholas Brown ◽  
Mark C Thompson ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Aerodynamic Drag ◽  
Time Trial ◽  
Force Measurements ◽  
Sampling Errors ◽  
Repeated Testing ◽  
Road Cycling ◽  
Wind Tunnel Study

The main aim of this study was to evaluate the potential to reduce the aerodynamic drag by studying road sprint cyclists’ positions. A male and a female professional road cyclist participated in this wind-tunnel study. Aerodynamic drag measurements are presented for a total of five out-of-seat sprinting positions for each of the athletes under representative competition conditions. The largest reduction in aerodynamic drag measured for each athlete relative to their standard sprinting positions varied between 17% and 27%. The majority of this reduction in aerodynamic drag could be accounted for by changes in the athlete’s projected frontal area. The largest variation in repeat drag coefficient area measurements of out-of-seat sprint positions was 5%, significantly higher than the typical <0.5% observed for repeated testing of time-trial cycling positions. The majority of variation in repeated drag coefficient area measurements was attributed to reproducibility of position and sampling errors associated with time-averaged force measurements of large fluctuating forces.

scholarly journals Estimation of an Airfoil Drag at High Angles of Attack from PIV Data

2019 ◽  
Vol 2019 (1) ◽  
pp. 28-36
Author(s):  
Austin M. Karr ◽  
Wit Stryczniewicz
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Attractive Alternative ◽  
Piv Technique ◽  
Image Velocimetry ◽  
Fluid Drag ◽  
Wind Tunnel Data ◽  
Low Speed Wind Tunnel ◽  
High Angles Of Attack

Abstract The paper presents application of Particle Image Velocimetry for determination of an airfoil’s drag coefficient in wind tunnel tests. The purpose of the study was to investigate the feasibility of using PIV as an alternative to pressure rake measurements, especially at high angles of attack. The integral momentum concept was applied for determination of fluid drag from experimental low speed wind tunnel data. The drag coefficient was calculated from velocity and pressure rake data for intermediate angles of attack from 5° to 10°. Additionally, the experimental results were compared to panel method results. After validating the procedures at low angles of attack, the drag coefficient was calculated at close to critical angles of attack. The presented study proved that PIV technique can be considered as an attractive alternative for drag coefficient determination of an airfoil.

A Wind-Tunnel Study of the Effect of Gap Flow and Gap Seals on the Aerodynamic Drag of Tractor-Trailer Trucks

1978 ◽  
Vol 100 (4) ◽  
pp. 434-438 ◽  
Author(s):  
F. T. Buckley ◽  
C. H. Marks
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Aerodynamic Drag ◽  
Motor Fuel ◽  
Center Line ◽  
Gap Flow ◽  
Yaw Angle ◽  
Wind Tunnel Study ◽  
Gap Width ◽  
Coefficient Reduction

The effect of gap width on the aerodynamic drag of a cab-over-engine tractor-trailer combination has been investigated for full-scale gap widths ranging from 0.61 m (24 in) to 1.83 m (72 in.) over a yaw angle range of 0 to 20 deg. The average drag on the vehicle was found to increase by 16 percent as the gap width increased from 0.61 m to 1.83 m. Drag reductions were found when a vertical seal was placed along the vehicle center line between the tractor and the trailer. Generally, the drag reduction increased as the percentage of gap width that was sealed increased, and as the yaw angle increased. The average drag coefficient reduction provided by a full gap seal increased from 0.02 to 0.05 as the gap width increased from 0.61 m to 1.4 m and then decreased slightly for gap widths up to 1.83 m. The effect of vehicle configuration on gap seal effectiveness was evaluated for a gap width of 1.3 m (51 in.) using models of six different tractors and two different trailers. The average drag coefficient reductions that were found ranged from 0.04 to 0.08 with 83 percent of the data being either 0.04 or 0.05. It is shown that the use of gap seals on the nearly half-million vehicles which comprise the nation’s long-haul trucking fleet can result in the conservation of about 1.4 × 109 liters (0.37 × 109 gal) of motor fuel each year.

scholarly journals Determination of the Drag Coefficient of an Autonomous Solar Lighting Column Using Wind Tunnel Simulation and Computational Analysis

2020 ◽  
Author(s):  
Vitor Hugo Da Silva Dias ◽  
João Carlos Almendra Roque ◽  
Sérgio Manuel De Sousa Rosa ◽  
Francisco Augusto Aparecido Gomes ◽  
Carlos Alberto Rodrigues Andrade
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Computational Analysis ◽  
Fluid Dynamic ◽  
Physical Analysis ◽  
Solar Panels ◽  
Computational Fluid Dynamic Analysis ◽  
Flowing Fluid ◽  
Solar Lighting

The Sun is the largest source of energy available and many studies for the development of technologies capable of harnessing this energy are constantly being conducted. Among the technologies developed are photovoltaic solar panels that have many applications and among them are the autonomous solar lighting columns that have been growing in popularity especially in urban and industrial environments. These columns are installed in open regions and have their structure exposed to the mechanical actions imposed by the wind, so they need to be correctly designed to support them. There are aerodynamic variables that must be determined for the design of these columns, especially the drag coefficient, a property linked to the geometry  of a body, which represents its interaction with a flowing fluid. Due to the complexity of determining these variables, experimental methods are constantly used to obtain these values. Classically, wind tunnel simulations are used for this purpose, but they can be expensive and difficult to perform. Fluid dynamic computational analysis has been widely applied to replace physical analysis. In this work, the drag coefficient of an autonomous solar lighting column is determined by wind tunnel simulations and computational analysis. With the obtained results, a comparison is made to verify  the fidelity of the data obtained by computational means when compared to those obtained through the wind tunnel simulations. Keywords: Drag coefficient, Wind tunnel simulations, Computational Fluid Dynamic analysis, Autonomous solar lighting columns

DETERMINATION OF MATERIAL CATALYCITY AT HIGH TEMPERATURES IN THE VAT-104 HYPERSONIC WIND TUNNEL

2014 ◽  
Vol 45 (1) ◽  
pp. 3-20 ◽  
Author(s):  
Ivan Vladimirovich Egorov ◽  
Boris Evgen'evich Zhestkov ◽  
Vladimir Viktorovich Shvedchenko
Keyword(s):  
Wind Tunnel ◽  
High Temperatures ◽  
Hypersonic Wind Tunnel
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