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Wind Tunnels in F1

Introduction


Formula 1 Racing is the highest level of motorsport and is governed by the Fédération Internationale de l'Automobile (FIA). When constructing a car to race, teams and engineers must follow a set of ‘formulas’ or rules to ensure fair racing. One way of ensuring the rules are the use of wind tunnels; large machines that generate an air current aimed at the car to test and analyse it’s aerodynamics during construction.


Aerodynamics in F1


Aerodynamics is the study of how air moves around things. The flow of air can influence the weight of a moving object and create lift and forces such as lift, drag, and thrust. Specifically to Formula 1, the main aim of aerodynamics is to generate downforce to push the tires harder into the road. With structures such as the front wing and floorboards, fast air is directed under the car which creates lower pressure and contrasts the high pressure air that is flowing on top of the car. Because of this difference in pressure, the car is essentially ‘sucked’ to the road -- this is downforce. The greater the downforce on the car, the more grip the tires have which enables the driver to move faster through corners, brake harder, and accelerate with efficiency.


For the car to perform optimally, it is important for downforce to be balanced throughout the rear and front wheels. Engineers can mimic this downforce through the use of wind tunnels. Information derived from mimicking this downforce can tell engineers changes they can make to the car and also help engineers, strategist, and even the driver better understand the car to optimize the car’s features.


Image is courtesy of The GSAL Journal


What are wind tunnels and why are they important?


Wind tunnels are a frequent tool used in aerodynamics research to study the effects of air moving past an object; in this case, Formula 1 looks at how the air passes around the car to maximise performance. Formula 1 testing relies on a closed circuit wind tunnel where the pathway of the air is circular and generates more uniform flow of air.


A main beneficiary of wind tunnels is that it helps engineers predict the performance of the car under ideal conditions due to the uniform flow of air aimed head-on at the car. Air flow on the track is unpredictable due variables like weather, track conditions, and other cars running on the track that can create dirty air -- the wake of air produced by a leading car that can disturb the aerodynamics of the car behind it. In addition, air flows differently when a car is turning and each turn is not completed exactly the same way. Thus, testing the car on an actual track is not the most accurate form of measuring air flow due to interfering variables.

Image is courtesy of Siemens


How do Wind Tunnels Work?


The insides of the wind tunnel are smooth so that the texture of surfaces do not cause disturbances in laminar air flow. The circuit of a wind tunnel is not a complete circle but rather a rectangle with round vertices. In these vertices where the airflow is turning, there are turning vanes. When air is turning a corner, air can be turbulent due to the change of direction of the walls. Turning vanes help ensure that the air remains it’s steady lines through these turns. Wind tunnels also have a drive section where a large fan spins to generate the air current. Following the drive section is a widening of the tunnel called the diffuser which slows the air down due to the increased volume. Next is the settling chamber where honeycomb-like grids help maintain laminar flow and straighten any turbulent air flows. The tunnel then narrows gradually towards the testing chamber where the testing car is located and this narrowing of the tunnel increases the speed of the air current over the car. After passing the car, the air passes through a corner and turns vanes back into the driving section, and the pathway of the air repeats again.



Image is courtesy of Technical F1 Dictionary


The model of the car that is used for testing in the wind tunnel must be reduced to 60% of it’s actual size according to the FIA. The vehicle is held in place by a vertical beam that helps engineers move the car in several directions to stimulate yaw (the turning of a car), pitch (acceleration and braking), and to adjust ride height. Smoke may be introduced into the air current so that the development team can visualize the air as it moves over the car. In addition, thousands of surface pressure tappings which are 0.05 mm holes connected with string gauges and diaphragms on the car allow for a better understanding of air pressure and provide a picture of air forces acting on the car.



Article Author: Ashley Chen

Article Editors: Maria Giroux, Valerie Shirobokov