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Old 05-12-2013, 10:08 AM   #1 (permalink)
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making a 8x8 foot cube aerodynamic...

Assuming I am starting with something like a box trailer, or a flatbed with a completely cubic load, what kind of aerodynamic treatment is appropriate to make?

The boattail out the rear is fine and a given, what i'm curious about is the front. I've seen some fairly blunt nosed designs under the argument that as long as laminar flow is maintained, that means low drag, and although bulbous a surprisingly flat front can still move air out of the way adequately enough (with a smooth tail) that 'needle nose fronts' arent needed until higher speeds.

Assume i'm working in cardboard, and maybe some thin scrap wood for structure if needed, if it matters...

Assuming a theoretical load of 8 feet wide, 8 feet tall, and 16-20 feet long, how long of a boattail would you make, what kind of work should I do to the front of the trailer mass to have it cut through the air better? Wedge pushing air to both sides, single wedge pushing air up (assuming it sticks out above the tow vehicle) smooth bulbous lump sticking forward... 1 foot? 3 feet?, etc?

How might this change if i'm trying to blend the flow from a pickup which is hauling the trailer, is it acceptable for the air to go 'down' into the pickup bed then back up to the trailer, or would having a topper on and trying to blend the sides/back of that to the actual 8x8 foot stack be better design?


For that matter how do you people model all this stuff up to know anyway, is there some freeware CAD program doing airflow that I can play with designs to learn how to aero-cize any load I might move in the future?

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Old 05-13-2013, 10:37 PM   #2 (permalink)
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Well, stillsearching, I would look for a box to your upper left that says "search ecomodder.com". Sorry.

There is a formula for the radius on the front edges, some % of the gross width. It can be a half-round on the flat front face. The rear could use a box cavity instead of a boat tail. I like Coanda nozzles.

If your handle was notsearching I'd give you the links.

Let me know if you need help.

CFD software requires super-computer level performance to give a meaningful result.
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Old 05-14-2013, 04:55 PM   #3 (permalink)
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How might this change

Quote:
Originally Posted by stillsearching View Post
Assuming I am starting with something like a box trailer, or a flatbed with a completely cubic load, what kind of aerodynamic treatment is appropriate to make?

The boattail out the rear is fine and a given, what i'm curious about is the front. I've seen some fairly blunt nosed designs under the argument that as long as laminar flow is maintained, that means low drag, and although bulbous a surprisingly flat front can still move air out of the way adequately enough (with a smooth tail) that 'needle nose fronts' arent needed until higher speeds.

Assume i'm working in cardboard, and maybe some thin scrap wood for structure if needed, if it matters...

Assuming a theoretical load of 8 feet wide, 8 feet tall, and 16-20 feet long, how long of a boattail would you make, what kind of work should I do to the front of the trailer mass to have it cut through the air better? Wedge pushing air to both sides, single wedge pushing air up (assuming it sticks out above the tow vehicle) smooth bulbous lump sticking forward... 1 foot? 3 feet?, etc?

How might this change if i'm trying to blend the flow from a pickup which is hauling the trailer, is it acceptable for the air to go 'down' into the pickup bed then back up to the trailer, or would having a topper on and trying to blend the sides/back of that to the actual 8x8 foot stack be better design?


For that matter how do you people model all this stuff up to know anyway, is there some freeware CAD program doing airflow that I can play with designs to learn how to aero-cize any load I might move in the future?
please see the thread 'Full-boat-tail trailer' on page-2,page 25 of the thread,#248 permalink for some ideas.
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Old 05-15-2013, 03:27 PM   #4 (permalink)
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A great search of this site, or even the web in general is "Dryden van". Or just search on my username.

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