Morelli's 'Fluid Tail'

[sendler]

Originally Posted by aerohead

*You'll have to help me with what you mean by 'cut-out.'

He's talking about the mirror which has a cut out in the step to allow the pathway for vision.
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This mirror is an example of what I am talking about regarding a concave area to set up the swirl. Even though Morelli doesn't specify a concave form, I think we would agree his research on this concept is incomplete. I would intuitively suggest that a concave form with a knife edged break leading to a quarter round inner wall/ base joint feature would be the most efficient shape in order to set up the rolling toroidal air formation needed for the root of the fluid tail. With a concave depth approaching half the narrow width of the outer oval.
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The inner round over might not make much difference but the concave depression seams obvious to me. I would love to see some comparative coast down data on the Prius with the concave truncated tail that was posted above. Even though it followed the body and was not perfectly oval, it looks like it would be very effective even though the swirl would not approach the ideal toroid motion because of the corners.

[aerohead]

Originally Posted by sendler

He's talking about the mirror which has a cut out in the step to allow the pathway for vision.
.
This mirror is an example of what I am talking about regarding a concave area to set up the swirl. Even though Morelli doesn't specify a concave form, I think we would agree his research on this concept is incomplete. I would intuitively suggest that a concave form with a knife edged break leading to a quarter round inner wall/ base joint feature would be the most efficient shape in order to set up the rolling toroidal air formation needed for the root of the fluid tail. With a concave depth approaching half the narrow width of the outer oval.
.
The inner round over might not make much difference but the concave depression seams obvious to me. I would love to see some comparative coast down data on the Prius with the concave truncated tail that was posted above. Even though it followed the body and was not perfectly oval, it looks like it would be very effective even though the swirl would not approach the ideal toroid motion because of the corners.

Okay,thanks!
Yes,the clear plastic portion is a box-cavity,which is capturing a locked-vortex,which the outer flow skips over like Morelli's fluid tail.
The length,and inset dimension of the cavity respect the ideal pathway.The 'cut-out' is just a practical consideration.
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The Prius extension is a box cavity as well,with a transverse separation line which gets equal pressure basically all around which is better for a higher base pressure and overall lower drag.
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It does lack Morelli's requirement for the transom geometry necessary for the fluid tail.If you look at the Fiat Punto mods,the roof extension appears to be softening the edge radii between the attachment point and trailing edge,rolling it and morphing into a more elliptical cross section.I did this with the CRX best I could.

[freebeard]

You'll have to help me with what you mean by 'cut-out.

What sendler said. I checked for a third page before I hit Submit for this:

Instead of the traverse cut it has a notch, which I presume is for the driver's sight-line. But the mirror is under the influence of a larger body, which might mitigate the sub-optimal form.

I thought there were wind tunnels that could add snow. Maybe they have heated leading edges.

The lower corners of that elliptical form are the hard part. Morelli resorted to pumped air from hubcaps, since he didn't have a flat-four air pump in the lower rear.

[aerohead]

Originally Posted by freebeard

What sendler said. I checked for a third page before I hit Submit for this:

Instead of the traverse cut it has a notch, which I presume is for the driver's sight-line. But the mirror is under the influence of a larger body, which might mitigate the sub-optimal form.

I thought there were wind tunnels that could add snow. Maybe they have heated leading edges.

The lower corners of that elliptical form are the hard part. Morelli resorted to pumped air from hubcaps, since he didn't have a flat-four air pump in the lower rear.

*Yes,in virtually all the tunnel photos we can see that the airflow in the mirror region is skewed,including my video from DARKO.There is a distance from the body at which the interference drag minimum of the mirror is optimized.If we don't get approval for camera systems,we may see more basic research into lower drag mirror systems.In the meantime,I'll be watching 24-hours of LeMans, LMP-1,race car technology.These teams do everything for a reason.
*In climatic wind tunnels,the turning vanes can be heated or cooled to maintain a constant air density during testing.(the air mover itself will inadvertently heat the airstream ).Freeze-testing is done in a climatic chamber I believe,separate from the wind tunnel.Eglin Air Force Base,Florida, has a chamber large enough to freeze a 747.
To allow snowflakes to impact the fan blades,at the velocities they run at could be devastating to the leading edges,as well as ruin the dynamic balance of the blades,potentially catastrophic.
*Yeah,if Morelli had the air-cooled boxer engine,he could have ducted the cooling air off the cylinders/heads' sheetmetal to help create the Coanda nozzles.He said they were losing 2/3rds of the air from the wheel turbines due to gap leakage.

[aerohead]

here's a peek at Kia's transom,compared to Morelli's first 'fluid-tailed' CNR of 1978

[MobilOne]

I'm still pondering Morelli's design with pick-up modifications in mind.

[cptsideways]

This appears to be a trend in some new car designs, check out the yet to come out LR Discovery, sporting some very obvious rear aero tweaks

[freebeard]

2010 KIA Ray concept

It looks like someone's been doing their homework.

cptsideways -- It's hard to see anything through the dazzle camo, but you've opened a door:


http://www.autoblog.com/2016/01/05/vw-budd-e-concept-ces-official/

The electric 'microbus' VW showed at CES. Capsule review: It looks like a BMW i3 got humped by some Ford. The seating layout, headrest/seat belt, the slide-out running board under the side door, the slide out trunk — all good, but the curved window line and solar panels means it will never have slot windows and a sunroof.

Anyone who has soldiered uphill, in the dark and rain, in an old microbus will be dismayed by the blue strip lighting in the grille and the mid-air hand gestures to open the doors. It does have a little shelf under the dashboard, but it won't hold anything, it's just decorative.

Back on-topic: I wonder if the aerodynamics would be better with that base plate extended or retracted.

[aerohead]

Originally Posted by MobilOne

I'm still pondering Morelli's design with pick-up modifications in mind.

Don't do what I did with the T-100 bedcover for sure.I'll have to redo all the sides,rolling in from the rail top,instead of the Jaray 'combination'-type plan-taper above the rails.

[aerohead]

Originally Posted by freebeard

2010 KIA Ray concept

It looks like someone's been doing their homework.

cptsideways -- It's hard to see anything through the dazzle camo, but you've opened a door:


http://www.autoblog.com/2016/01/05/vw-budd-e-concept-ces-official/

The electric 'microbus' VW showed at CES. Capsule review: It looks like a BMW i3 got humped by some Ford. The seating layout, headrest/seat belt, the slide-out running board under the side door, the slide out trunk — all good, but the curved window line and solar panels means it will never have slot windows and a sunroof.

Anyone who has soldiered uphill, in the dark and rain, in an old microbus will be dismayed by the blue strip lighting in the grille and the mid-air hand gestures to open the doors. It does have a little shelf under the dashboard, but it won't hold anything, it's just decorative.

Back on-topic: I wonder if the aerodynamics would be better with that base plate extended or retracted.

The base plate must be an entire fraction of the transom area,and must be at zero yaw to have a chance.
With the partial base plate,at zero yaw,if there were reattachment and vortex capture,there'd be a pressure conflict between the original wake remnant,and the smaller new wake,causing vortex-induce drag.