Aerodynamics Without using CFD 2

[carla00]

Hi There,

A quick question, In the past I have used CFD to look at styling on cars, however I don't have CFD any more.

Do you think it would be possible to get a basic idea of how effective aerodynamic aids are at differing speeds without the use of CFD ?

 

[rb1957]

try old text books like Hoerner "Fluid Dynamic Drag" and
"... Lift". These books are intended for airplanes ... maybe there are more specific books for cars

good luck

 

[GregLocock]

Yes, look in Hucho , "aerodynamics for road vehicles".

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[SkyD]

You're right guys, text book are your best guest. For me your best Guess Carla is "Race Car Aerodynamic, Designing for Speed" by Joseph Katz. Definitely a must have in terms of car aerodynamic. You can complete that by another one of his books: "Low Speed Aerodynamic" which is a bit more directed to aircrafts but has some useful stuff in it...

Cheers,
SkyD

 

[cdx]

You could go " Old school " and tape little pieces of yarn all over your car.
Find some deserted stretch of road and have a friend drive beside you and video the car.

( Next thing you know you will see the video all over the internet and you will be forced to move to some small island ....... no - not really !

Actually, I am sure you are well aware of 'tuft testing'.

Where the strips of yarn stick to the car and barely flutter, there is little turbulence.
Where the strips of yarn begin to twirl and flutter, the airflow has turbulence.
You can also add drops of oil to an area directly in front of where you want to test. As you get up to speed, the drops of oil will ether puddle, or trail outward.
Just be carefull not mess up the cars paint.

All of this is of little help if the car you are talking about only exists as a CAD file. ( You could always perform the tests on a large scale model.)

Good luck !