Aerodynamics in Rain

[miqi23]

Thought it would be great to start a topic on Aerodynamics in wet conditions.

Just wondering what every one thinks about Multiphase flows! (Water and Air)

It would be great to have some contribution from every one.

Thanks a lot.

[DaveKillens]

The thing is, as soon as wet conditions are there, the engineers crank as much download into the car's aero as possible. As well, wet or intermediate tires have maximum diameter as possible, while dry tires have less diameter. That is so when the car runs in the wet, it's body sits higher than when dry. That is to allow more (and softer) suspension travel to improve grip.
But water has much more mass than air, so it's flow around shapes would be quite different than air.

[mep]

DaveKillens wrote:That is to allow more (and softer) suspension travel to improve grip.

If they are able to change the suspension setup then they are also able
to let the car run higer in general, so this is no reason for a biger tire diameter.

But sometimes it starts to rain during the race and in this case they are unable to change the setup. So the only possibility to ingrease the high of
the car is to let it run on tires with a biger diameter. Thats exactly the reason

[ss.vamsikrishna]

yes actually when the rain falls there will be a sleet or layer of water on the track so height of the car has to be increased as the air which flows
below the car like in a venturi tube it flows at very high speed creating lot
of downforce as pressure is very less (bernolli 's principle) but due to this layer of water and car's low height air flow may sieze and create no downforce that will be really fatal so they increase the height..