Brilliant way to visualise/see air/fluid flow

[freebeard]

Aren't all cylinders rectangular? Excepting [s]non-parallel[/s[ right angle end caps?

My point had to do with putting a balance beam with two models in a wind tunnel. (Or on a platform on a moving vehicle).

At Permalink #29 I showed Wally Byam's teardrop with a 50% radius on the front edges. Airstream have brought this back in their Base Camp model.

[j-c-c]

IMO to retain some authenticity to the "teardrop" moniker, seems at the least the overall shape needs to be nonsymmetrical on at least one plane.

[freebeard]

Else aerohead's half-body in profile with inadequate fineness ratio.

My geodesic approximation of the half body is asymmetrical on two planes.

[aerohead]

Originally Posted by freebeard

Aren't all cylinders rectangular? Excepting [s]non-parallel[/s[ right angle end caps?

My point had to do with putting a balance beam with two models in a wind tunnel. (Or on a platform on a moving vehicle).

At Permalink #29 I showed Wally Byam's teardrop with a 50% radius on the front edges. Airstream have brought this back in their Base Camp model.

* I'm not in possession of the necessary data from which to accurately answer that question.
* I chose 'square', as, from a 'forwards', or 'rearwards' observation point, most RV travel trailers have a 'rectangular' footprint.
* If you design edge radii from the 'height', it won't match the 'sides,' and vice versa.
* By using the square-root of the frontal area, you get a 'compromise' radius which agrees all-around ( this was formally presented as an an aerodynamic 'solution' in Hucho's 2nd Edition book ).
-----------------------------------------------------------------------------------
* I don't comprehend what you're describing when you you use the term 'balance beam', and I'm reluctant to speculate.
* I see no advantage to Wally's design, nor the Base Camp's.
* 'Aerodynamically,' there would be no gap between the TV and TT.
* Their frontal areas would be equally matched also ( take a look at El Paso ( Texas ) Sun Metro's, NFI Group's, low-floor, articulated, 100% gap-filled, pusher-trailer transit buses ).https://www.flickr.com/photos/drum118/48193865117

[aerohead]

Originally Posted by freebeard

Else aerohead's half-body in profile with inadequate fineness ratio.

My geodesic approximation of the half body is asymmetrical on two planes.

That's a good way to put it!
When the aft-body portion is less than 350% of the body's 'thickness' ( V ),the attendant super-deceleration of the flow creates the adverse pressure gradient that triggers flow separation ( at the heart of what Fachsenfeld / Kamm found at the FKFS, around 1935 ).
These 'bluff' rear ends are responsible for crappy, vortex-induced drag and lift coefficients.
The 'double-frontal-area' pressure signature of the 'double-hump' TV/TT 'system' aggravates the situation.
A 'real' aerodynamicist would insist on an aerodynamic 'singularity.'

[freebeard]

Originally Posted by aerohead

* I don't comprehend what you're describing when you you use the term 'balance beam', and I'm reluctant to speculate.

Being from Texas, perhaps your familiar with a singletree?

https://chimacumtack.com › blog › 2017 › 09 › 02 › singletrees-eveners
Singletrees and Eveners | Chimacum Tack
According to Webster's New World Dictionary a single tree is a bar attached at the center of the hitch on a wagon, carriage or plow which is hooked at either end to the traces of the horse's harness. The function of the single is to balance the weight being pulled. The singletree is mounted on a post or pin

Originally Posted by aerohead

* I see no advantage to Wally's design, nor the Base Camp's.

An aerodynamic compromise to accommodate interior headroom?

[aerohead]

here's some considerations:
1) in order to guarantee reliable quanta, you'd be looking at, at least, 40%-scale models.
2) considering the depreciation in the value of the US Dollar between 1990 and now, a single model would run you about $152,000.
3) there are no wind tunnels to my knowledge that will accommodate two models, side-by-side in a test section.
4) you'd be limited to testing each separately, then comparing the data.
5) from the left coast, to the right coast and back is a 6,000-mile trip.
6) at 14-mpg, pulling a two-model trailer, and $3.30/gallon, your fuel would be $1,414.
7) motels would run around $1,680.
8) meals about $840.
9) wind tunnel time, in a rolling-road test section is gonna be $4,000 / hour, times 2, for $8,000.
10) for one person, one 'test', about $ 316, 348.
--------------------------------------------------------------------------------------
11) if you had your two, ($ 304,414) models, and could get them 3-D scanned, and imported into something like AirShaper, you could save a little over $ 3,900 using CFD.
------------------------------------------------------------------------------------
12) the models would be too large to place side-by-side atop even the first of three flatbed railcars, pushed from behind by a single locomotive, as has been done in the past for 'single' models.
13) The flow interference between the two would 'wreck' the test, and vibration from the rails would probably ruin the load cell null calibration and any subsequent measurements.
--------------------------------------------------------------------------------------
14) if your talking about TVs & TTs tested as a unit together, you've just 'doubled' your expense, and I'm unsure who could even navigate that kind of testing. NASA's Ames Research Center in Palo Alto, California is one of the few tunnels that can handle TV/TT combinations. And you typically need a DARPA grant to even gain access to the facility, the ' world's largest '.