Drag Reduction System in f1 Cars

  • View

  • Download

Embed Size (px)

Text of Drag Reduction System in f1 Cars

DRAG REDUCTION SYSTEM IN F1 CARSINTRODUCTION TO AERODYNAMICS Aerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a moving object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with the difference being that gas dynamics applies to all gases. Understanding the motion of air (often called a flow field) around an object enables the calculation of forces and moments acting on the object. Typical properties calculated for a flow field include velocity, pressure, density and temperature as a function of position and time. By defining a control volume around the flow field, equations for the conservation of mass, momentum, and energy can be defined and used to solve for the properties. The use of aerodynamics through mathematicalanalysis, empirical approximations, wind tunnel experimentation, and computer simulations form the scientific basis for heavier-than-air flight. Aerodynamic problems can be classified according to the flow environment. External aerodynamics is the study of flow around solid objects of various shapes. Evaluating the lift and drag on an airplane or the shock waves that form in front of the nose of a rocket are examples of external aerodynamics. Internal aerodynamics is the study of flow through passages in solid objects. For instance, internal aerodynamics encompasses the study of the airflow through a jet engine or through an air conditioning pipe. In fluid dynamics, drag (sometimes called air resistance or fluid resistance) refers to forces which act on a solid object in the direction of the relative fluid flow velocity. Unlike other resistive forces such as dry friction, which is nearly independent of velocity, drag forces depend on velocity.[5] Drag forces always decrease fluid velocity relative to the solid object in the fluid's path. As such minimizing drag is a major objective to achieve high speeds as in case of planes as well as the very fast Formula 1 cars. Lift is the force that directly opposes the weight of an object and holds it in the air Lift occurs when a solid object turns a moving flow of gas. A negative lift causes downforce, which is the force that acts to push an object closer to the ground. Lift and downforce are basically the same except that downforce acts downward and lift acts upward.

Why You Need Aerodynamics

Not only can better aerodynamics help improve the speed of a car, but it can also better the efficiency of a car Proper aerodynamic shaping, has been found to be the most effective and least costly method of increasing fuel economy and performance, especially at higher speeds Automotive aerodynamics also plays an important role in other related areas including:

high-speed traction, sensitivity to crosswinds, efficient cooling (engine, drive train, exhaust system, and brakes), keeping the front windshield, the windows, the mirrors and the headlights clean, and last but not least, reducing wind noise to a minimum

USE OF AERODYNAMICS IN F1 CARS The rear wing of a modern Formula One car, with three aerodynamic elements (1, 2, 3). The rows of holes for adjustment of the angle of attack (4) and installation of another element (5) are visible on the wing's endplate. The use of aerodynamics to increase the cars' grip was pioneered in Formula One in the late 1960s by Lotus, Ferrari and Brabham. Wings Early designs linked wings directly to the suspension, but several accidents led to rules stating that wings must be fixed rigidly to the chassis. The cars' aerodynamics are designed to provide maximum downforce with a minimum of drag; every part of the bodywork is designed with this aim in mind. Like most open wheeler cars they feature large front and rear aerofoils, but they are far more developed than American open wheel racers, which depend more on suspension tuning; for instance, the nose is raised above the centre of the front aerofoil, allowing its entire width to provide downforce. The front and rear wings are highly sculpted and extremely fine 'tuned', along with the rest of the body such as the turning vanes beneath the nose, bargeboards, sidepods, underbody, and the rear diffuser. They also feature aerodynamic appendages that direct the airflow. Such an extreme level of aerodynamic development means that an F1 car produces much more downforce than any other open-wheel formula; for example the Indycars produce downforce equal to their weight at 190 km/h (118 mph), while an F1 car achieves the same downforce:weight ratio of 1:1 at 125 to 130 km/h (78 to 81 mph), and at 190 km/h (118 mph) the ratio is roughly 2:1.[6] The bargeboards in particular are designed, shaped, configured, adjusted and positioned not to create downforce directly, as with a conventional wing or underbody venturi, but to

create vortices from the air spillage at their edges. The use of vortices is a significant feature of the latest breeds of F1 cars. Since a vortex is a rotating fluid that creates a low pressure zone at its centre, creating vortices lowers the overall local pressure of the air. Since low pressure is what is desired under the car, as it allows normal atmospheric pressure to press the car down from the top, by creating vortices downforce can be augmented while still staying within the rules prohibiting ground effects.[dubious discuss] The new F1 cars for the 2009 season have come under much questioning especially the rear diffusers of the Brawn GP cars raced by Jenson Button and Rubens Barrichello. Appeals from many of the teams were heard by the FIA, which met in Paris, before the 2009 Chinese Grand Prix and the use of diffusers was declared as legal. Brawn GP boss Ross Brawn claimed the diffuser design as "an innovative approach of an existing idea". Ground effects F1 regulations heavily limit the use of ground effect aerodynamics, which are a highly efficient means of creating downforce with a relatively small drag penalty. The underside of the vehicle, the undertray, must be flat between the axles. A 10mm[7] thick wooden plank or skid block runs down the middle of the car to prevent the cars from running low enough to contact the track surface; this skid block is measured before and after a race. Should the plank be less than 9 mm thick after the race, the car is disqualified. A substantial amount of downforce is provided by using a rear diffuser which rises from the undertray at the rear axle to the actual rear of the bodywork. The limitations on ground effects, limited size of the wings (requiring use at high angles of attack to create sufficient downforce), and vortices created by open wheels lead to a high aerodynamic drag coefficient (about 1 according to Minardi's technical director Gabriele Tredozi;[8] compare with the average modern saloon car (sedan in the USA), which has a Cd value between 0.25 and 0.35), so that, despite the enormous power output of the engines, the top speed of these cars is less than that of World War II vintage Mercedes-Benz and Auto Union Silver Arrows racers. However, this drag is more than compensated for by the ability to corner at extremely high speed. The aerodynamics are adjusted for each track; with a relatively low drag configuration for tracks where high speed is relatively more important like Autodromo Nazionale Monza, and a high traction configuration for tracks where cornering is more important, like the Circuit de Monaco.

Race-car aerodynamicsIn recent years motor racing has become one of the most popular of sports, attracting record numbers of followers. In some racing categories the vehicles resemble production sedans while in others they look more like fighter airplanes, and there is also a great variety of tracks that range from paved to unpaved and from straight to oval or regular road courses. In all forms of racing, however, aerodynamics eventually surfaced as a significant design parameter, and nowadays all race-car designs have some level of aerodynamic element. The complexity of racecar aerodynamics is comparable to airplane aerodynamics and is not limited to drag reduction. The generation of aerodynamic downforce (force directed downward, or negative lift) and its effect on lateral stability result in a major enhancement in race-car performance, particularly when high-speed turns are involved. In the process of designing and refining current race-car shapes, all available aerospace type design tools are used. Because of effects such as flow

separation, vortex flows, and boundary-layer transitions, the flow over most types of race cars is not easily predictable. Owing to the competitive nature of this sport and the short design cycles, engineering decisions must rely on information gathered from track and wind-tunnel testing, and even computational fluid dynamics. Although the foundations of aerodynamics were formulated over the past 200 years, not all its principles were immediately utilized by race-car designers. Naturally, the desire for low drag was recognized first, and early designers focused mainly on streamlining their race cars. Although there was some experimentation with the addition of wings to influence the vertical load on the vehicle during the late 1920s, this major innovation was completely ignored for the following 35 years. Once designers realized the significance of aerodynamic downforce and its effect on vehicle performance, fixtures such as inverted wings or even underbody diffusers were added. The benefits of aerodynamic downforce and the improved performance are basically a result of increasing the tire adhesion by simply pushing the tires more toward the ground. Because of this additional load, larger friction (traction) levels can be achieved, and the vehicle can turn, accelerate, and brake more quickly. Furthermore, by controlling the fore/aft downforce ratio,