scholarly journals Wind Tunnel Tests to Reduce Aerodynamic Drag of Trains by Smoothing the Under-floor Construction

2001 ◽  
Vol 42 (2) ◽  
pp. 94-97 ◽  
Author(s):  
Atsushi IDO ◽  
Yoshihiko KONDO ◽  
Tsuyoshi MATSUMURA ◽  
Minoru SUZUKI ◽  
Tatsuo MAEDA
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Drag ◽  
Wind Tunnel Tests

scholarly journals Impact of wheel rotation on the aerodynamic drag of a time trial cyclist

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
Fabio Malizia ◽  
T. van Druenen ◽  
B. Blocken
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Aerodynamic Drag ◽  
Front Wheel ◽  
Wind Tunnel Tests ◽  
Wheel Rotation ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Drag Area

AbstractAerodynamic drag is the main resistive force in cycling at high speeds and on flat terrain. In wind tunnel tests or computational fluid dynamics simulations, the aerodynamic drag of cycling wheels is often investigated isolated from the rest of the bicycle, and sometimes in static rather than rotating conditions. It is not yet clear how these testing and simulating conditions influence the wheel aerodynamic performance and how the inclusion of wheel rotation influences the overall measured or computed cyclist drag. This study presents computational fluid dynamics simulations, validated with wind tunnel tests, that indicate that an isolated static spoked front wheel has a 2.2% larger drag area than the same wheel when rotating, and that a non-isolated static spoked front wheel has a 7.1% larger drag area than its rotating counterpart. However, rotating wheels are also subjected to the rotational moment, which increases the total power required to rotate and translate the wheel compared to static conditions where only translation is considered. The interaction with the bicycle frame and forks lowers the drag area of the front wheel by 8.8% for static and by 12.9% for the rotating condition, compared to the drag area of the isolated wheels. A different flow behavior is also found for static versus rotating wheels: large low-pressure regions develop from the hub for rotating wheels, together with a lower streamwise velocity region inside the circumference of the wheel compared to static wheels. The results are intended to help in the selection of testing/simulating methodologies for cycling spoked wheels.

scholarly journals Wind Tunnel Tests of Influence of Boosters and Fins on Aerodynamic Characteristics of the Experimental Rocket Platform

2017 ◽  
Vol 2017 (4) ◽  
pp. 82-102
Author(s):  
Paweł Ruchała ◽  
Robert Placek ◽  
Wit Stryczniewicz ◽  
Jan Matyszewski ◽  
Dawid Cieśliński ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Drag ◽  
Wind Tunnel Test ◽  
Longitudinal Axis ◽  
Aerodynamic Characteristics ◽  
Scale Model ◽  
Wind Tunnel Tests ◽  
Aerodynamic Loads ◽  
Microgravity Experiments ◽  
Image Velocimetry

Abstract The paper presents results of wind tunnel tests of the Experimental Rocket Platform (ERP), which is developed in Institute of Aviation. It is designed as an easy accessible and affordable platform for microgravity experiments. Proposed design enables to perform experiments in microgravity for almost 150 seconds with apogee of about 100 km. The full-scale model of the ERP has been investigated in the T-3 wind tunnel in Institute of Aviation. During the investigation, the aerodynamic loads of the rocket has been measured for the angle of attack up to 10° and the different rotation angle around the longitudinal axis (up to 90°, depending on the configuration). Three configurations has been investigated: • without fins and boosters • with fins and without boosters • with fins and boosters Additionally, the measurements of velocity field around the ERP using the Particle Image Velocimetry (PIV) has been performed. Based on the wind tunnel test, an influence of fins and boosters on aerodynamic characteristics of the rocket has been described. Results of the wind tunnel tests show relatively high contribution of boosters in total aerodynamic drag. Some conclusions concerning performance and stability of the rocket have been presented.

Methods for Reducing Aerodynamic Drag on Cargo Carrying Railcars

2014 ◽  
Author(s):  
Robert Condie ◽  
Daniel Maynes
Keyword(s):  
Experimental Data ◽  
Wind Tunnel ◽  
Diesel Fuel ◽  
Aerodynamic Drag ◽  
Void Space ◽  
Wind Tunnel Tests ◽  
Large Void ◽  
Roof Structure ◽  
Shipping Costs ◽  
The Cost

In recent years the cost of diesel fuel has increased sharply and this has led to an interest in reducing shipping costs by train. Current manufacturing practices of railcars provide an opportunity for research in methods that reduce the aerodynamic drag. This paper reports on a study which involved collecting experimental data from wind tunnel tests using 1/29 scale train models. Two cargo carrying railcar types were studied. The first were coal carrying railcars and the second were auto carrying railcars. Different features of the railcars were investigated. The largest contributor to drag on the coal cars is the large void space of an empty car. The research investigates several roof structures that cover this space and act to reduce drag. From these structures it is determined that the drag can potentially be reduced by nominally 46%. Similarly, profile features of the auto carrying railcars are also investigated. This research reviewed the roof structure, side panels and chassis structure. From the data, it was determined that drag could be reduced by modifying or covering the roof, side panels and chassis structure by nominally 20%, 5% and 15% respectively.

EFFECTS OF HELICOPTER HORIZONTAL TAIL CONFIGURATIONS ON AERODYNAMIC DRAG CHARACTERISTICS

2017 ◽  
Vol 79 (7-4) ◽  
Author(s):  
Iskandar Shah Ishak ◽  
Muhammad Fitri Mougamadou Zabaroulla
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Aerodynamic Drag ◽  
Angle Of Attack ◽  
Aerodynamic Efficiency ◽  
Wind Tunnel Tests ◽  
Tunnel Model ◽  
The Subject ◽  
And Performance ◽  
Selection Of

Experimental aerodynamic investigations remain the subject of interest in rotorcraft community since the flow around the helicopter is dominated by complex aerodynamics and flow interaction phenomena. The objective of this study is to determine the aerodynamic drag characteristics of helicopter horizontal tail by conducting wind tunnel tests. To fulfil the objective, three of the most common helicopter horizontal tail configurations namely Forward Stabilizer, Low-aft Stabilizer and T-tail Stabilizer, were fabricated as a simplified scaled-down wind tunnel model mated with a standard ellipsoidal fuselage. The test wind speed for this experimental work was 30 m/s, determined from Reynolds sweep, which was corresponding to Reynolds number of 2.8 x 105. Wind tunnel tests were performed at variations angle of attack ranging from -15O to 15O with 5O interval. The results tell that at zero yaw and zero pitch angles, Forward Stabilizer contributed the least drag coefficient at 0.277 implying the configuration could be the best for cruising flight segment. Contrarily to T-tail Stabilizer, this configuration contributed the most drag coefficient at 0.303, which was 9% higher than the former. The T-tail Stabilizer was also found to be the most sensitive to the change of angle of attack where the drag was drastically increased up to 131.35% at -15O angle of attack compares to at zero angle of attack. These findings had successfully testified that the type of stabilizer configuration does significantly influencing the aerodynamic drag characteristics of helicopter. Subsequently, the selection of stabilizer must wisely be done to have the best aerodynamic efficiency and performance for the helicopter. 

scholarly journals Wind tunnel model tests of Magnus type wind rotors with a horizontal rotation axis

2013 ◽  
Vol 12 (2) ◽  
pp. 151-156
Author(s):  
Piotr Matys ◽  
Andrzej Flaga
Keyword(s):  
Wind Tunnel ◽  
Lift Force ◽  
Aerodynamic Drag ◽  
Rotation Axis ◽  
Rotating Cylinder ◽  
Model Tests ◽  
Horizontal Axis ◽  
Wind Tunnel Model ◽  
Wind Tunnel Tests ◽  
Tunnel Model

The paper presents results of wind tunnel tests of horizontal axis wind  rotors of Magnus type. Firstly, measurements of aerodynamic side (lift) force and aerodynamic drag on rotating cylinder attached to horizontal aerodynamic balance were performed. Secondly, the model of single-blade rotor with counterbalance was tested.

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