scholarly journals Some Observations on Shape Factors Influencing Aerodynamic Lift on Passenger Cars

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 44
Author(s):  
Jeff Howell ◽  
Steve Windsor ◽  
Martin Passmore
Keyword(s):  
Wind Tunnel ◽  
High Performance ◽  
Aerodynamic Drag ◽  
Small Scale ◽  
Shape Features ◽  
Passenger Cars ◽  
Shape Factors ◽  
Front End ◽  
Factors Influencing ◽  
Aerodynamic Lift

The car aerodynamicist developing passenger cars is primarily interested in reducing aerodynamic drag. Considerably less attention is paid to the lift characteristics except in the case of high-performance cars. Lift, however, can have an effect on both performance and stability, even at moderate speeds. In this paper, the basic shape features which affect lift and the lift distribution, as determined from the axle loads, are examined from wind tunnel tests on various small-scale bodies representing passenger cars. In most cases, the effects of yaw are also considered. The front-end shape is found to have very little effect on overall lift, although it can influence the lift distribution. The shape of the rear end of the car, however, is shown to be highly influential on the lift. The add-on components and other features can have a significant effect on the lift characteristics of real passenger cars and are briefly discussed. The increase in lift at yaw is, surprisingly, almost independent of shape, as shown for the simple bodies. This characteristic is less pronounced on real passenger cars but lift increase at yaw is shown to rise with vehicle length.

scholarly journals Vehicle Ride Height Change Due To Radial Expansion Of Tires

2015 ◽  
Vol 13 (2) ◽  
pp. 22-27
Author(s):  
Ondřej Čavoj ◽  
Ondřej Blaťák ◽  
Petr Hejtmánek ◽  
Jan Vančura
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Drag ◽  
Vertical Displacement ◽  
Radial Expansion ◽  
Ride Height ◽  
The Road ◽  
Vehicle Aerodynamics ◽  
Height Change ◽  
On The Road ◽  
Aerodynamic Lift

Abstract In general, tire deformations caused by wheel rotation are not taken into account when developing vehicle aerodynamics. On the road the tires radially expand as speed increases, which affects the actual ride height of a vehicle. In turn this often increases the real aerodynamic drag compared to values obtained using CFD or a wind tunnel as the mass flow across the relatively rough underbody increases with ground clearance. In this study, on-road ride heights were measured while running a vehicle in a straight line with fixed velocity whilst the aerodynamic lift of the vehicle was determined in a wind tunnel. Subsequently, the relationships between ride height and axle load were obtained by loading the vehicle at standstill with ballast. By comparing the ride heights at high and very low velocities with expected vertical displacement caused purely by aerodynamic lift force as computed according to the ride height - axle load equations, the ride height change due to tire radial expansion was determined.

Wind Tunnel Experiments to Assess the Effect of Back-Mounted Radio Transmitters on Bird Body Drag

1988 ◽  
Vol 135 (1) ◽  
pp. 265-273 ◽  
Author(s):  
HOLLIDAY H. OBRECHT ◽  
C. J. PENNYCUICK ◽  
MARK R. FULLER
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Drag ◽  
Substantial Reduction ◽  
Frontal Area ◽  
Flight Performance ◽  
Wind Tunnel Experiments ◽  
Front End ◽  
Body Drag ◽  
Radio Transmitters ◽  
Performance Estimates

To whom reprint requests should be addressed. The aerodynamic drag of bird bodies was measured in a wind tunnel, with and without back-mounted dummy radio transmitters. Flight performance estimates indicate that the drag of a large transmitter can cause a substantial reduction of a migrant's range, that is, the distance it can cover in non-stop flight. The drag of the transmitter can be reduced by arranging the components in an elongated shape, so minimizing the frontal area. The addition of a rounded fairing to the front end, and a pointed fairing behind, was found to reduce the drag of the transmitter by about onethird, as compared with an unfaired rectangular box.

scholarly journals An Investigation of Aerodynamic Effects of Body Morphing for Passenger Cars in Close-Proximity

Fluids ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 64
Author(s):  
Geoffrey Le Good ◽  
Max Resnick ◽  
Peter Boardman ◽  
Brian Clough
Keyword(s):  
Large Scale ◽  
Aerodynamic Drag ◽  
Autonomous Vehicle ◽  
Small Scale ◽  
Bluff Bodies ◽  
Passenger Cars ◽  
Current Trends ◽  
Close Proximity ◽  
Potential Energy Saving ◽  
The Individual

The potential energy-saving benefit for vehicles when travelling in a ‘platoon’ formation results from the reduction in total aerodynamic drag which may result from the interaction of bluff bodies in close-proximity. Early investigations of platooning, prompted by problems of congestion, had shown the potential for drag reduction but was not pursued. More recently, technologies developed for connected-autonomous vehicle control have provided a renewed interest in platooning particularly within the commercial vehicle industry. To date, most aerodynamics-based considerations of platooning have been conducted to assess the sensitivity of drag-saving to vehicle spacing and were based on formations of identically shaped constituents. In this study, the interest was the sensitivity of drag-saving to the shape of the individual platoon constituents. A new reference car, the Resnick model, was specially designed to include front and rear-end add-on sections to make distinct changes in profile form and simulate large-scale body morphing. The results of wind tunnel tests on small-scale models suggested that current trends in low-drag styling may not provide the ideal shape for platoon constituent members and that optimised forms are likely to be dependent upon position in the platoon.

scholarly journals Methods of Reducing Vehicle Aerodynamic Drag

2012 ◽  
Author(s):  
Volodymyr Sirenko ◽  
Roman Pavlovs’ky ◽  
Upendra S. Rohatgi
Keyword(s):  
Wind Tunnel ◽  
Drag Reduction ◽  
Aerodynamic Drag ◽  
Vortex Generators ◽  
Scale Model ◽  
Small Scale ◽  
General Motor ◽  
Passive Devices ◽  
Partial Implementation ◽  
Small Scale Model

A small scale model (length 1710 mm) of General Motor SUV was built and tested in the wind tunnel for expected wind conditions and road clearance. Two passive devices, rear screen which is plate behind the car and rear fairing where the end of the car is aerodynamically extended, were incorporated in the model and tested in the wind tunnel for different wind conditions. The conclusion is that rear screen could reduce drag up to 6.5% and rear fairing can reduce the drag by 26%. There were additional tests for front edging and rear vortex generators. The results for drag reduction were mixed. It should be noted that there are aesthetic and practical considerations that may allow only partial implementation of these or any drag reduction options.

Bestimmung der Dauerhaftigkeit von Hochleistungsbeton mit Hilfe des CDF-Tests / Determination of the durability of high performance concrete by means of CDF-test

1999 ◽  
Vol 5 (1) ◽  
pp. 29-40
Author(s):  
R. Krumbach ◽  
U. Schmelter ◽  
K. Seyfarth
Keyword(s):  
Frost Resistance ◽  
High Strength Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Concrete ◽  
Factors Influencing

Abstract Variable obsen>ations concerning frost resistance of high performance concrete have been made. The question arises which are the decisive factors influencing durability under the action of frost and de-icing salt. The proposed experiments are to be carried out in cooperation with F.A.- Finger - Institute of Bauhaus University Weimar. The aim of this study is to determine possible change of durability of high strength concrete, and to investigate the origin thereof. Measures to reduce the risk of reduced durability have to be found.

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