pickup mid-body aerodynamics? (neither nose nor tail)

[stillsearching]

I started in this direction of thought in another thread then realized it probably needs it's own discussion...


In a situation of say an aeromodded front with a pickup... and an aeromodded trailer with a boat tail... how important is the in-between area? I know people talk about trying to blend/connect the tow vehicle to the trailer, but I was also wondering how the aero of the open pickup bed and such affects it. Some tests have shown that under some conditions having the pickup tailgate up instead of down is better aero. Driving With Tailgate Up Is Fuel Efficient : Discovery Channel I am curious whether the "separated bubble" is the same FE as say, a topper connected to a trailer of similar profile.. whether it's only the laminar flow that matters, or whether the 'bubble' still causes some drag even if less drag than you think because of smooth flow.

What i'm wondering is whether you might be able to use some kind of similar 'trick' on say the front edge of one body like a bit of a lip to kick the airflow out slightly, to get the airflow to go right to the trailer, without actually being physically connected and without any real increase in drag...

[JRMichler]

The answers to your questions, in this and your other threads are in this book: Aerodynamics of Road Vehicles: From Fluid Mechanics to Vehicle Engineering ([Proceedings] / SAE): Wolf-Heinrich Hucho: 9780768000290: Amazon.com: Books

Hucho is THE source for these type questions.

[freebeard]

Ecomodder (specifically aerohead) is the source for examples gleaned from Hucho.

...a bit of a lip to kick the airflow out slightly...

This doesn't happen.

[Big Dave]

Aerohead actually somewhat understands Hucho, which puts him ahead of me.

[aerohead]

Originally Posted by stillsearching

I started in this direction of thought in another thread then realized it probably needs it's own discussion...


In a situation of say an aeromodded front with a pickup... and an aeromodded trailer with a boat tail... how important is the in-between area? I know people talk about trying to blend/connect the tow vehicle to the trailer, but I was also wondering how the aero of the open pickup bed and such affects it. Some tests have shown that under some conditions having the pickup tailgate up instead of down is better aero. Driving With Tailgate Up Is Fuel Efficient : Discovery Channel I am curious whether the "separated bubble" is the same FE as say, a topper connected to a trailer of similar profile.. whether it's only the laminar flow that matters, or whether the 'bubble' still causes some drag even if less drag than you think because of smooth flow.

What i'm wondering is whether you might be able to use some kind of similar 'trick' on say the front edge of one body like a bit of a lip to kick the airflow out slightly, to get the airflow to go right to the trailer, without actually being physically connected and without any real increase in drag...

Please see the thread 'full-boat-tail trailer',on page 2 of the forum,then page-25 of the thread,#248 permalink.You'll find a graphic I made from Abbott and Von Doenhoff's 'The Theory of Wing Sections,' and you can see the difference in drag based on 'gaps' and where the gaps are positioned on the wing.