henra wrote:shelly wrote:
Yes they could reduce drag becuse of lower pressure on the fornt face of the tyre. But porbably this is not the case - the perspective is tricky.
Even if they might achieve a marginally lower local pressure in front of a small part of the tyre the vortex will obstruct flow along the coke bottle which is otherwise allowing significant pressure recovery there. The net effect will be surely negative.
Moreover as @trinidefender has pointed out it did cost significant drag to generate the vortex in the first place.
We don't know the properties of the flow around coke bottle. Most likely it is very complicated from interaction of tyre, coanda-exhaust the flow around sidepods. The vortex generation indeed creates drag, but if it has some positive effect on the area, it could well diminish the net drag. Another possibility is it helps produce more downforce.
It is not the first picture where intensive vortices are seen coming from the front of the car.
As was mentioned by
trinidefender F/A-18 is using LERX to produce vortices, but many more fighter aircrafts use same strategy: F-16, F-22, EuroFighter, Rafale, Su-27 and Mig-29 etc. It is known and used from the late-60s/mid-70s.
Here's an example of Su-35 fighter
The vortices are designed to keep the flow over the wings attached and the also energies flow over rudders, thus making aircraft more stable in yaw at high A-o-A.