canard for bluff bodied box

[bluebunny]

Hi Folks,
Your inputs have really helped me get my thoughts around the idea that I was trying to present; Thank you. In order to clarify the idea, I think it time to summarize what I was attempting to present?

What I have presented was actually misrepresented as a canard (wing). In actuality, it is a truncated bubble; a leading edge add-on. If it were placed materially above the top or side edge, then yes, it would be a thin-plate wing. But in its near-height with the box surface, it is only a leading edge radius, with two exceptions: it is a truncated radius; it has a venturi nozzle (the slot) in a spot that “may” be situated to help control the boundary layer and delay a separation along the box edge. It materially should not affect the cross sectional flow area as a canard or Flugel-type turning vane might?

I have only a few more speculations;
1. Truncated leading edge radii won't work as well as full frontal bubbles; if you have the room, go for the full bubble with large radii.
2. The cross-sectional flow area of the truncated leading edge might only handle about twice the cross sectional area of the box-body, so larger box areas need larger devices.
3. These truncated devices need strong construction and solid mounting.
4. The underneath device (the inner arc) is critical to nozzle performance, and nozzle throat inlet-to-outlet area is probably critical but may not optimized in the presented design.

Without flow testing of some type, further discussions may lead some astray. I don’t wish for my rhetoric here to fool anyone that this may be a solution without testing.

My original and final agenda is/was for someone to take an interest as prove or disprove the idea in testing. We all know how not-intuitive vehicular flows can be.
Flow software, anyone?
Kind Regards,
Butch Kuhn

[niky]

Originally Posted by freebeard

How does it open up, as a dump?

Not quite sure, just pulled that off the net because it's faster than raiding my incredibly poorly organized picture library... but similar ones have the rear door top-hinged, just tilt the entire bin and the stuff drops out the back.

[freebeard]

Kind Regards,
Butch Kuhn

I'll always think of you as bluebunny.

What I have presented was actually misrepresented as a canard (wing).

I didn't see any point in calling you on that. It's essentially a fixed leading-edge slot.

Agreed that the concept needs testing and that it would need to resist forces similar to a massive air dam. And in the real world, it would need to resist icing up in Winter.

[aerohead]

With zero-yaw flow,for a leading edge,your after just enough radius to get the flow attached,which would be a fraction of the body width,or a fraction of the square-root of the frontal area.It's been researched both ways.
If you do the blown slot as shown,the upper surface is above the plane of the roof,which is separation right there.
The slot introduces a jet of air which disrupts the pressure profile of the air around it,adding an aerodynamic 'kink',to the body,and it aggravates the growth of the local boundary layer,which we'd like to minimize as much as possible,as well as have as uniform as possible.
For crosswind conditions (mostly the real world of motoring) a bulbous nose has an advantage over all other leading edges.
Here's some examples of 'fixes' for a trailer


Killing the gap is even better

[freebeard]

Does that Toyota-branded trailer pre-date the Ecomodders doing the same thing?

[kach22i]

Check out this thread for a similar discussion.

http://ecomodder.com/forum/showthrea...ure-33061.html

[freebeard]

Now that's a Hot VW.

[rumdog]

Interesting air intake behind the cab. We used to watch truck racing in NZ when I was a kid. Good times

[bluebunny]

Originally Posted by aerohead

With zero-yaw flow,for a leading edge,your after just enough radius to get the flow attached,which would be a fraction of the body width,or a fraction of the square-root of the frontal area.It's been researched both ways.
If you do the blown slot as shown,the upper surface is above the plane of the roof,which is separation right there.
The slot introduces a jet of air which disrupts the pressure profile of the air around it,adding an aerodynamic 'kink',to the body,and it aggravates the growth of the local boundary layer,which we'd like to minimize as much as possible,as well as have as uniform as possible.
For crosswind conditions (mostly the real world of motoring) a bulbous nose has an advantage over all other leading edges.

The radiused add-on's upper surface would be a fraction of an inch above the plane of the surface; I agree it is a disturbance, albeit a small and smooth one, with induced surface flow...

It is in the yawed flow, where the free stream flow is flowing away from the plane of the surface, where the slot might contribute to delay separation? The stronger the yaw, the stronger the slot should perform, and perform similar to a slotted wing to improve attachment? It sure benefits wings at high yaws! It's also known that wing slots are hurtful at low yaws, so maybe the net-net benefit for slots is negative, unless the plane of the surface normally falls away from the free-stream flow?

[aerohead]

Originally Posted by freebeard

Does that Toyota-branded trailer pre-date the Ecomodders doing the same thing?

I saw Dr. Paul MacCready's patent in the mid-1980s,which is the original invention for this sort of thing,so it predates EcoModder.