along withcarWith the advent of the times, the term "car culture" has gradually become known to people, and a brand-new car culture is also quietly emerging. It is what attracts all car fans who pursue individuality and speed.Car modification. This article will introduce the application of aerodynamics in the modification. There are not lack of theoretical bluntness, but there are also some practical content. You will have an understanding of the application of aerodynamics in the modification process.
We know that the influence of the body design is enough to change the high-speed performance of the car in an all-round way. From extreme speed, stability to economic performance, it can be closely related to this. Now when discussing cars, aerodynamics is a major theme that cannot be ignored.
Aerodynamics is a difficult measurement science in the field of science. When a car is in motion, it will cause an unavoidable impact on the relatively static air, and the air will flow around, and the airflow that enters the bottom of the car will be unavoidable. It will be temporarily trapped in the various mechanical parts under the car, and the air will be pulled by the moving car, so when a car speeds past, the paper and leaves on the ground will be rolled up. In addition, the airflow under the car will generate a buoyant lift in the front of the car and the engine compartment, weaken the downforce of the wheels on the ground, and affect the handling performance of the car. In addition, the fuel of the car has consumed a large part of the power when it is burned to promote the operation of the machine, and when the car is running at high speed, a part of the power will also be used to overcome the resistance of the air. Therefore, the significance of aerodynamics for car design is not only to improve the handling of the car, but also a trick to reduce fuel consumption.
Ways to deal with buoyancy
One way to deal with buoyancy is to use a spoiler under the car. However, there are very few mass-produced cars using this device today. The main reason is that the R&D and manufacturing costs are too high. Among recent production cars, only FERRARI 360M, LOTUS ESPRIT, and NISSAN SKYLINE GT-R still use such devices.
Another mainstream approach is to install a sturdy baffle under the front of the car that is slightly longer than the front of the car.It can direct airflow to the hood, or throughWater tankThe grille and flow through the body. As for the rear part of the car, the main issue is how to make the air flow smoothly through the body, and the air flow in the rear of the car should be kept as neat as possible.
If the air flowing through the car body can be close to the contour of the car body when the car is running, we call it ATTECHED or LAMINAR (the so-called streamlined). The shape of the water droplet is the most streamlined shape we know today. However, it is not that the car has to be designed in the shape of a water drop to achieve the best LAMINAR. In fact, the traditional car shape can also achieve a good LAMIAR effect. The common method is to control the inclination angle of the rear windshield within 25 degrees.
In fact, by carefully observing the side of this kind of coupe, it is not difficult to find that the line from the front to the rear of the car will be curved upwards toward the roof, while the bottom of the car is very flat. In fact, this shape is similar to the shape of the wing section. When the air flows over this wing-shaped object, the gas flowing from above the car body must flow faster than from below the car body, which will generate a buoyancy force. As the speed increases, the downforce loss will gradually increase. Although the pressure difference between the top and bottom of the car body may be only a little bit, due to the larger area of the top and bottom of the car body, a slight pressure difference will cause a significant difference in grip. Generally speaking, the rear of the car is more susceptible to the effects of buoyancy, and the front part of the car will also cause handling and stability problems.
Traditional motorhomes, station wagons, and hatchbacks have a relatively vertical rear windshield. The effect of buoyancy on them is slight, because the airflow has been scattered after passing through the vertical rear window, forming the so-called turbulence effect. As a result, the buoyancy force drops, but these turbulences are also the source of the airflow pulling force. Some studies have pointed out that for hatchbacks like GOLF, if the angle between the roof and the tail window is within 30 degrees, the airflow tension caused by it will be lower than that of the design with more than 30 degrees. So some people will take it for granted that as long as the angle between the rear window and the roof is controlled between 28 and 32 degrees, the issues of buoyancy and air tension can be taken into account at the same time. In fact, the problem is not that simple. In this angle range, the airflow can neither close to the car body nor cause turbulence, so it is difficult to predict the air flow. Because the car is not driving on a level surface when it is driving, as the suspension system moves up and down, in fact, the distance of the car from the ground is a variable, and the pressure difference caused by the air flowing through the car body will change at any time. The airflow dynamics at the left and right of the rear of the vehicle when the vehicle is cornering will also affect the airflow at the rear of the vehicle. When the angle between the rear window and the roof is between 28 and 32 degrees, the rear of the car will be on the edge of stability and instability, which is actually very dangerous. For example, AUDI TT had a high-speed rollover problem when it was launched. The accident investigation report pointed out that the buoyancy of the rear axle of AUDI TT was too high at high speed, which caused the rear wheel grip to be too weak. The TT takes style as the primary prerequisite when designing, and sacrifices aerodynamics. The curvature of the rear window and the rear of the car is between the above embarrassing angle. When designing hatchbacks, car manufacturers prefer to design the rear of the car to be straight. First, it can increase the space in the car, and secondly, it also overcomes the lack of aerodynamics.
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