Formula one is an exciting sport and has a strong following. It has recently also picked up more traction owing to the expansion of location of races. A Formula one car itself is a marvel of mechanical engineering. On a top-speed straight, a formula one car attains sufficient speed to take flight, if not for the downforce that holds it down. The front wing and rear wings play a critical role in the overall aerodynamics of a formula one car. 2017 brings about drastic changes to the regulations that would increase the aesthetics of the car alongside bringing lap times down by up to 5s. The video by motorsport.com visually shows the changes between 2016 and 2017.
This article looks at the design of front wing of an F1 car and possible ideas for improving the overall aerodynamics. However, before proceeding ahead, it is pertinent to understand the regulations, including dimensions etc, regarding an F1 car.
Change in Regulations: 2016 and 2017
Fig. 1 and 2 show the screenshots from the video by motorsport.com and it visually depicts the differences in regulations, regarding dimensions between 2016 and 2017.
In particular, Fig. 1 and 2 shows the main change between 2016 and 2017, is the change in the dimension of the F1 car’s front wing from 1800 mm to 2000 mm.
For more extensive details on the regulations, we can re-direct you to the regulations part on the website of FIA.
Aerodynamic Design
Aerodynamics play a fundamental role in the overall set up of a Formula One car. An air duct panel between the front wheel and the side panel, for instance, can add more speed than two or three extra horsepower. The teams invest as much as up to 20% of their total budget in understanding the aerodynamics of the car. Modern F1 cars can drive corners much faster than normal, commercial cars and this would not be possible without downforce.
Meticulous precision work is undertaken using computations and experiments in wind tunnels to accurately tailor the wings and the wind deflectors to the last millimeter. This design is aimed at increasing the downforce and reducing the drag. This also permits shorter braking distances and higher cornering speeds. The downforce generates 80% of the grip required for the car. F1 cars can withstand centrifugal forces of up to 4G without sliding off the track primarily due to the aerodynamic designs allowing high cornering speeds. This would be impossible without downforce and thus ensures performance and safety.
But downforce is not the only aspect of the ideal situation is to find a balance between greatest possible downforce and lowest air resistance. There is no one particular design that works for all circuits. Depending on the speed and type of the circuit, different configurations are ideal. There are more than 20 settings in the rear wing, over 100 settings for the front wing. However, there is only one ideal condition. The teams need to adjust the configuration for an ideal performance in each race and the team that gets nearest to the ideal conditions wins.
For example, the Italian Grand Prix in Monza has long straights and fast corners and is considered a high-speed circuit. Here, the teams use flat wings to gain the highest possible speeds. In contrast, in circuits with lots of narrow corners (like Monaco), wing elements with a steep setting is used. This helps generate maximum downforce possible for the cars to drive through the corners faster. Though it is commonly believed that the front wings are responsible for about one-third of the downforce, this can drastically reduce to one-tenth if there is a car directly ahead. Apart from the front wing, about half of the downforce is due to the diffusers on the vehicle underbody. These lead the flowing air towards the rear creating a strong suction effect.
Most large F1 teams have wind tunnels to experiment. However, SimScale offers an excellent platform to use CFD simulations that can facilitate reducing in experimentation and associated costs and yet accurately tune the parameters using computational models.
Importance of Front Wing in a Formula One Car
Before proceeding ahead, it becomes very much important to understand the role of the front wing in a Formula one car. The front wing works in the opposite way of how an aircraft wing works. While an aircraft wing produces lift, the front wing produces a downforce to keep the car from taking off! In other words, the airfoil of a front wing is profiled so that it helps keep the car on the ground and wheels in contact with the surface. Thus, it plays a major role in ensuring sufficient grip and traction for the car.
In addition to controlling the downforce, the front wings also control the total airflow around the car. Being the first part of the car that the air comes in contact with, the front wing also governs the overall aerodynamics of the F1 car. One of the function is also to direct the airflow in a way that is optimized for the aerodynamics of the car. Just to get an idea regarding the contributions to downforce and drag, we can direct you to the article on “What parts of a Formula 1 car generate the main aerodynamic forces?“.
Front Wing Design
The front wing is designed in a shape that is opposite of an airfoil. Can you guess why? Yes, to prevent it from taking off! The front wing (or the main plane) is suspended from the nose and runs along the entire length of the car. To this main plane, adjustable flaps are attached and at the ends of the main plane, the end plates are attached. The different parts of the front-wing are shown marked in Fig. 03.
The main flaps and the end plate make sure that the wind flows above and beneath the airfoil. The end plates especially play a part in re-directing the air flow around the tires which are aerodynamically bad.
End plate design
End plates are one of the very important aspects of the front wing. Optimization of their position and shape can significantly help improve the overall aerodynamics. The end plates have 5–10 times more effect than most other parts. They control the flow of air around the car by redirecting the airflow around the tires. This minimizes the overall drag resistance produced and facilitate the air to flow to continue back to the side pods and the car floor.
During the years, there have been several changes and at present, the wheels are much nearer to the chassis than several years ago. In addition, the tips of the front wings coincide with the ends of the tires. This creates unnecessary turbulence in front of the wheels and increases drag. Hence, the inside edges of the end plates are curved to ensure that the air flows around the tires. Fig 04. shows the air flow around the end plate.
In addition, the endplate stops the high-pressure air on the top of the wing from rolling over the wing to the low-pressure air beneath, causing an induced drag. This is also an aspect to watch out for during the simulations. Similarly, the endplates do not allow “turbulent” air created by the front tire from getting under the floor of the car. Further to assist in the functionality of the end plates, some cars also use vertical fences, called splitter, attached to the undersurface of the front wing.
Tip 01: For a great performance, ensure that the end plates minimize airflow from top to the bottom of the car. Do the endplates also facilitate the air flow to go around the wheels?
Wing Flaps
The wing flaps on either side of the nose cone are asymmetrical such that their height is lesser near the nose cone. This arrangement facilitates the air to flow into the radiators and to the underfloor. If the height of the wing flap is same as the nose cone this would reduce the overall air to the radiators and thereby leads to a rise in engine temperatures.
The asymmetrical shape also allows a better air flow to the underfloor and the diffuser, increasing downforce. The wing mainplane is by the FIA rules flat in the center and same design for all cars, again by the rules. This again allows a slightly better airflow to the underfloor aerodynamics, but it also reduces the wings ride height sensitivity. The main area of development is the wing profile interaction with the front wing endplate.
Tip 02: How do the changes in the front wing profile and end plate affect the air flow profiles around / on each other?
Flow control Techniques
We looked at the effect of each element of the front wing on the overall aerodynamic balance of the car. Yet, the big elephant in the room remains unaddressed — “All the theory sounds great but what elements could we use to make it better?“! Some elements that one can think about to alter the flow field include vortex generators, blowing / suction elements and moving surfaces.
Vortex generators
These are the first fix for any flow problem. They try to modify the flow by redistribution of the overall momentum. The fluid with high momentum is brought into the boundary layer. Below is an interesting Youtube video for a more detailed explanation on how vortex generators work.
Concisely, VG’s prevent flow separation. They are generally around the height of the local boundary layer and are generally placed around 20 times local boundary layer height ahead of the point of separation. They can be used to generate vortex suction, add downforce and help to guide the flow.
Blowing / Suction Elements
Blowing can be used to inject high energy air into the boundary layer and suction to remove the tired boundary layer. They are not generally widely used due to power requirement and additional weights. Yet, both of these are very interesting ideas that can be used efficiently to reduce drag through careful design of the blowing/suction slot. Some of the most famous ones being the Maclaren F-duct, Lotus drag reduction and Red Bull S-duct.
Moving surfaces
Moving surfaces have not been used so far on the front wing but definitely an idea for the future. The idea rests in creating a surface that moves at the same speed as the flow and thus reducing the relative motion. This could be an extreme way to manage the flow. Yet, each year new innovations are what keeps the sport interesting through reduced lap times, more feasibility for overtaking maneuvers etc.
Conclusions
The greatest shortcoming of CFD simulations has been to consider the wake (or turbulent behavior) accurately. For example, one of the trickiest ones is in modeling the wake between the front wing and the tires. Ensuring good discretization and accurate turbulent models in regions of interest could govern the accuracy of the predictions made using CFD simulations.
For more detailed discussions on the analysis including CAD models to start from, we would recommend the SimScale F1 Aerodynamics Workshop Series. In particular, the session one addresses the design and aerodynamics of a front wing. As we can see from the discussions, front wing design, development, and optimization are not just about adding downforce, but more importantly about cleaning the air flow towards rest of the car and crucially provide stability when turning through corners.
Happy computing!
With more than 30 years of engineering experience in the automotive industry, Carlsson Autotechnik GmbH provides engineering services for companies like Mercedes-Benz, Citroen, Peugeot, Honda, Toyota and SsangYoung. This case study shows how the engineers from Carlsson used SimScale to test the aerodynamics behavior of their sports car.
Originally published at www.simscale.com on October 21, 2016.
