Static pressure behind a vehicle

[Caito]

Hi all,


I know that usually behind a moving a vehicle there's a pressure lower than atmospheric.

Do you have any idea how much, or how to calculate? I'm looking mostly into trucks (let's say a flat back) rather than racecars.

I've found nice plots but with no absolute values.


Thanks for your help!
Caito

[Greg Locock]

In the example, the pressure is probably dark blue = ambient-.2*1/2*rho*v^2

[e36jon]

Greetings Caito

If big truck aero is an interest area you would really dig "Aerodynamics of Road Vehicles" by Hucho. Large vehicle aero gets a bunch of coverage (buses, trains too.). And in general it is a superb text on aero, if a bit dated. (I don't know if they have revved the edition since my copy which was published in 1987.)

Here in the U.S. there has been (finally) quite a bit of movement recently on aero devices for semis, so we are seeing things like flush wheel covers, under trailer 'barge-boards', and even foldable tapered tail fairings... (All of which are covered in the book. Nothing new under the sun?)

Good luck with your project!

Jon

[Caito]

Thanks for the replies!!