These days, the human mind has been conditioned in a number of ways. If one talks about aircraft, one automatically thinks about airplanes, helicopters, military fighter aircraft, … However, what this basically comes down to is people automatically think about either ‘stationary’ wings, turbines and propellers. Stationary wings do have a few moving parts to influence the created amount of lift, but are not what causes lift to happen. This is normal, because when we look up in the sky, this is exactly the only things we see.
However, if we look up, we actually see another type of aircraft: the birds. What is special about them is the way they propel themselves through the air. Instead of stationary wings, they flap their wings to propel them forward. This of course is nothing new, everybody knows how birds transport themselves. however, one might wonder if this could also be applied to manmade machines that mimic the their way of transport.
As the video below already might suggest, this was indeed possible. With the help of Festo, which is specialized in electric and pneumatic transducers, a team of engineers made a robotic bird which can fly around the same way real birds do. This just goes to show that nature indeed holds a lot of answers to certain problems we are faced with and that it’s definitely worth looking into. The industrial applications of this are probably nonexistent, it’s hard to imagine an airplane that flies around using this as propulsion. However, this indicates that there are still other possibilities than what the modern day has already discovered. You can watch the entire video below:
As stated in the previous post, aerodynamical adaptions are a very efficient way of boosting a vehicles performance. The following technique is a lot more complicated than the bio-mimicry discussed before, however this method holds great promise. The biggest difference is that one should make a whole lot of adaptions and is not something just anyone can accomplish. The technique is called ‘Boundary layer suction’.
Without going into too much detail, the boundary layer is the region closest to an object wherein the speed internally differs. In other words, one ‘layer’ of air has a different speed than the layer immediately above or below it, which results in viscous friction. This flow in general is closely attached to the surface and doesn’t let go, however, this layer can separate from the surface and causes a large increase in drag. This happens for example when the angle of attack of a wing becomes too high and stall occurs.
The idea behind boundary layer suction is that one sucks away this layer before it has the chance to separate. This not only increases the extent to where the flow stays attached, one also is able to extend the range of the laminar flow, decreasing the drag even more. However, this suction also costs energy, so one should try to calculate the net gain in energy before considering this technique. It holds great opportunities for aerospace, but would it be something also applicable to cars as well?
If you looked at the starting grid of the 2012 Le Mans race, you could see one weird car which goes against all traditional design rules for racing cars.
It has no spoilers or wings, no big wide tire and a small frontal area. You might wonder how a car like that could still be fast on a race track but it was. This is because the designers just took a whole new fresh approach to the problems of endurance racing.
They wanted to design a car that has half the drag of a normal car, with half the weight and half the tire wear, which would result in less pit stops because of a lower fuel consumption.
And the designers did a great job with it. It was racing very well during Le Mans but it was unfortunately hit by another car and had to quit the race.
It was however not good enough to compete with the best cars among the grid which is the reason why we will probably not see any more of these designs in the near future but it was very pleasant and interesting to see such a new and fresh approach which ignored all the set conventions of race car design.
If one wants to boost the performance of their vehicle, improving the aerodynamics is a very good way to do it. However, people who are not well known with the principles of aerodynamics don’t know that, even if they don’t wish to alternate the initial shape of their car, they are still able to improve their performance without alternating the shape of their car.
Without going too much into the details, when a car moves forward (or backwards), the air has to flow around the car so that the car can move through. This causes viscous friction between the car and the air which causes a force working against the movement of the car, thus slowing it down. This friction force is dependent on the surface the air is flowing over and therefore you can improve this drag force by alternating the surface.
In general, a rough surface is considered to be bad for the performance. However, there are some exceptions. If bio-mimicry has taught me anything, it is that looking at nature often has a lot of answers to a lot of the nowadays questions. Just by looking at animals who have to live in similar conditions, on might find how these animals deal with such problems. The one that have gotten a lot of attention lately are sharks. Sharkskin has a special pattern that improves the flow around them, meaning they have to use less energy to move around.
These days, this pattern is also adapted to swimsuits of competitive swimmers in order to boost their performance. So in theory, this should also be applicable to cars. These days, a few are experimenting with applying this technique on vehicles and are getting good results. This way, a relatively simple coating could easily reduce the drag forces working upon cars and make them more efficient. So within a few years, you might be able to buy one of these with a coating already on it.
Since the start of our thesis, it became very clear to us that if you wanted to study something in the area of fluid dynamics, CFD software would almost always be a necessity. CFD stands for Computational Fluid Dynamics and indicates the branch of fluid dynamics where one uses numerical methods and algorithms to solve problems instead of a practical approach in windtunnels. Mostly when studies are conducted, a CFD study is done as a start or means for optimization with an actual case study in a windtunnel for verification of the results.
When it comes to CFD software, there are 2 main names you come by very often, being ‘Ansys Fluent’ and ‘OpenFOAM’. Although both do a very good job, there are some key differences. For example, Ansys works with a license based package, has a very good GUI and is fairly easy to use. OpenFOAM however is an open source software, has a very limited GUI, mostly runs on scripts and runs on Linux, which makes it harder for starters to work with the software.
However, a third player is slowly but surely making its way into the market: Numeca. It’s a Belgian company located in Brussels which was founded in the 1992. They are nowadays present on a broad spectrum of industries, going from Aerospace to even Healthcare. The company started off as a Spin-Off of the Vrije Universiteit Brussel and now has offices worldwide. One of the software’s that caught my eye was the ‘AutoGrid’ which is capable of applying a high quality mesh for a number of application. Since the results of CFD are highly dependent on the quality of the mesh, this tool is very helpful to increase the accuracy of the results, if used properly of course. A quick example can be seen below:
Chances are you will hear a lot more of this company in the coming years.
A few years ago, just after the introduction of KERS in F1, Williams teamed up with Porsche to equip a GT3 race car with a similar KERS system to the one Williams uses in its F1 cars. As discussed in a previous post, this was one of the strategies of Williams to gain money to fund its F1 team. The Porsche 911 GT3 R will use an electro-mechanical flywheel system which stores the energy in a flywheel and sends it back to the front wheels with electric motors.
Selling such technologies to other car companies seems a very good strategic decision to me. It helps to spread the technology and because of the fact that technology advances very fast in a motorsport environment, it will help to develop KERS systems which can be used in normal road cars or other forms of civil transportation.
Certainly in urban areas, this can save a lot of energy which would otherwise be lost as heat in the brakes.
Year after year, more and more studies are conducted in order to prove the necessity of green and sustainable technologies in order to ensure a healthy and wealthy future. One market that could surely benefit form this is the car industry, which is currently investigating the possibility of carbon monocoque structures over steel frames. These engineers are constantly looking for new ways to make travel less polluted and much more fuel efficient. And the Formula One sport is no different.
Each year, new regulations are set up to force and inspire the teams to go even further in order to get the most performance out of the little fuel they get. This causes new technologies to be developed that could also be used in regular cars. The changes this year are so incredible that the teams has to almost completely redo their design in order to meet the new regulations. The video below gives a short explanation as to what has changed this year:
The teams this year had to go very far in order to make it work, but how much further will they actually be able to go?