Refine Your Search

Search Results

Viewing 1 to 11 of 11
Technical Paper

Study of an Open-Wheel Racing-Car's Rear-Wing Aerodynamics

The effect of a race-car's rear-wing shape on its high-lift aerodynamic characteristics was investigated numerically and experimentally. These geometrical variations included parameters such as wing leading-edge sweep, several chord-wise elements, addition of trailing edge flaps and of side fins. The main advantage of the numerical computations was to allow for the investigation of a large number of wing geometries without an expensive and lengthy fabrication process of similar wind-tunnel models. Results of this study indicate that complying with the current Championship Auto Racing Teams (CART) regulations, a rear wing with a lift coefficient on the order of −2.2 (based on wing's reference area) is possible.
Technical Paper

Rapid, Low-Cost, Aerodynamic Development of a High-Performance Sports Car

A two-seat sports car was designed with the initial marketing goal of breaking the Laguna-Seca racetrack record. This study reports the external aerodynamic modifications that resulted in a significant increase in the vehicle's downforce. The main objective of this study is to report about the method used, which was significantly simpler and much faster than traditional methods used by the automotive industry. Because of the simplicity of the tools used (e.g., computations and wind tunnel), valid engineering conclusions could have been reached only by combining these tools.
Technical Paper

Lateral Aerodynamics of a Generic Sprint Car Configuration

The aerodynamic characteristics of a sprint car model were tested in a small-scale wind tunnel. Lateral characteristics such as the side force and rolling moment were measured in addition to the vehicle's downforce and drag. Measured data indicated that during the rapid cornering of these race cars, lateral loads are as important as downforce. Since literature search revealed no aerodynamic data on such asymmetric vehicles, a typical baseline sprint car model was tested first with particular focus on large sideslip conditions. Modified wing and side fin geometries were also tested for improved visibility and in search for additional downforce. The experimental data indicate, for example, that a reduced endplate size of the main wing can improve driver visibility without significant loss of aerodynamic downforce.
Technical Paper

Investigation of Negative Lifting Surfaces Attached to an Open-Wheel Racing Car Configuration

Aerodynamic lift and drag coefficients of various open-wheel racing car configurations were experimentally investigated. These configurations included several basic fuselage shapes which, in view of the current regulations, did not make use of the “ground effect” to provide negative lift. To these fuselage shapes, which had some positive lift, both unswept wings and delta wings were added to increase their negative lift. The experiments were made with one-tenth scale models, but in order to evaluate these results, comparison is made with full-scale wind tunnel experiments. The results of this work show that useful conclusions can be drawn, based on the small-scale tests, about the relative effectiveness of these aerodynamic devices. Furthermore, with the aid of these lifting surfaces an overall lift coefficient of about minus one was found to be obtainable.
Technical Paper

Full-Scale, Ort-Road Study of the Effect of Automobile Shape on its Aerodynamic Characteristics, and Comparison with Small-Scale Wind Tunnel Results

The design of passenger vehicles for improved aerodynamic characteristics will result in reduced fuel consumption and better road handling during high-speed driving. In this research, techniques were developed to measure the aerodynamic drag and lift forces acting on a full-scale vehicle under road conditions and then were compared with results obtained on reduced-scale models in a wind tunnel. A number of configurations which characterize common vehicle forms were investigated for their effect on aerodynamic efficiency and fuel consumption, Experimental speeds were between 70 and 110 km/h, these being representative of highway driving conditions. A typical passenger vehicle of the three-box type was selected for the experiments, and its exterior form was altered by means of attaching various configurations to its front, rear, and underbody portions.
Technical Paper

Effect of Wing/Body Interaction on the Aerodynamics of Two Generic Racing Cars

The influence of a rear-mounted wing on the aerodynamics of two generic race car configurations was investigated. Both body-surface pressure and vehicle lift data indicate that the wing/body interaction is large and that, by proper placement of the wing over the body, total downforce coefficients that are considerably larger than the sum of the isolated downforce of the wing and body can be obtained. The above interaction also alters the pressure distribution and spanwise loading on the wing; therefore, the design process for such airfoils should account for the detailed three-dimensional flow field created by the body (contrary to the traditional assumption of placing the wing in an undisturbed free stream).
Technical Paper

Application of Computational Methods to the Aerodynamic Development of a Prototype Race Car

A three-dimensional computer simulation technique was combined with wind-tunnel testing during the aerodynamic development of an enclosed-wheel prototype race car. This approach proved that valuable time can be saved by investigating some of the important design parameters before a vehicle is built. One of the major advantages of a computational approach is that it contains information such as pressure or velocity distribution on and near the whole vehicle. This abundance of data is essential for understanding major design trends and sensitivities, and can steer the design toward fruitful modifications. Once the vehicle's body plan is finalized, the method can be used to further modify local details and to design and position a complicated rear wing cluster. At this phase of wing design, the availability of the pressure distribution on the entire wing surfaces is vital to a successful design.
Technical Paper

Aerodynamics and Possible Alleviation of Top Fuel Dragster ‘Blow Over’

During a high-speed drag race a race-car nose may accidentally be lifted by the aerodynamic loads causing the dangerous ‘Blow Over’ phenomenon. Such aerodynamic loads were investigated for a wide range of pitch angles in small-scale wind-tunnel tests, using a Top-Fuel Dragster model. A simple device, creating negative vortex lift, was proposed and tested in an effort to reduce the pitch up moments during the initial phases of the ‘Blow Over’. Results of the wind tunnel tests indicate that when deploying the proposed device, immediately after the front wheel liftoff, alleviation of the ‘Blow Over’ is possible.
Technical Paper

Aerodynamic Model for Wing-Generated Down Force on Open-Wheel-Racing-Car Configurations

A simplified panel model was constructed for determining wing-generated down force for open-wheel-racing-car configurations. The model required simulation of the separated wakes emanating from the vehicle's body and wheels. Separation line locations were assumed to be known from experiments or observation and, for simplicity, were fixed throughout all computations. Once the model for the vehicle body and wheels was established, inverted lifting surfaces were added to generate down force. The performance of these inverted lifting devices was then numerically investigated and compared with experimental data of a generic, Formula one, race car shape.
Technical Paper

Aerodynamic Effects of Indy Car Components

A generic, Indy-type, open-wheel, racecar model was tested in a low speed, fixed ground wind tunnel. The elevated ground plane method was selected for the road simulation since one of the objectives was to allow flow visualization under the car (and this is not possible with current rolling ground wind tunnel setups). Consequently, both the groundplane and the wind tunnel floor were transparent to facilitate the flow visualization under the vehicle. The aerodynamic loads were measured by a six-component balance, and an effort was made to quantify the partial contributions of the various vehicle components. The main trends and aerodynamic interactions measured with this setup appear to be similar to data measured in larger wind tunnels using rolling ground simulations. As expected, the two wings and the underbody vortex generators generated most of the aerodynamic downforce.
Technical Paper

A Systematic Approach to the Preliminary Aerodynamic Design of Enclosed-Wheel Racecars

The flow field over a vehicle and the resulting integral quantities, such as downforce and drag are a direct outcome of the vehicle's shape. During the initial developmental stage, therefore, it would be beneficial to have an inverse capability, dictating vehicle shape, based on a prescribed set of desirable aerodynamic parameters. Although such methods exist for airfoil design, their extension to complex vehicle geometries is far more complicated. Consequently, an alternate approach is experimented with here, whereby a desirable trend in the surface pressure distribution is specified. Using an iterative method, the vehicle shape is modified until the ‘target’ trend in the pressure distribution is met. In the present study such a systematic approach was proposed and used to develop an enclosed wheel racecar shape. During this process of refining the vehicles geometry, computational fluid dynamic tools were used.