Want low drag? Don't follow a template.

[freebeard]

Try all caps.

[JulianEdgar]

Originally Posted by elhigh

Or he has a job and can't be expected to spend all his time refuting every assertion. That's possible. We've had some nutty statements fly around here.

Sure. But I think it's very different when a newcomer, asking for aerodynamic modification advice, is given a bunch of crap based around a mythical template - and people who actually know better, say nothing.

Maybe I am the only one those newcomers write to, saying how they cannot understand how their measurements and observations don't match what everyone else (apparently) endorses?

To use an old fashioned phrase, it makes my blood boil to see people being misled in this way.

[Vekke]

If you have the better way to do these shapes show and tell us how your basic shapes should be used with some samples to get better results?.

Again I havent seen any information to prove your points. Its that simple. At the moment you are too misleading if there is no results or exaples shown.

Also I would appreciate if you could answer my previous questions as this is a forum where we talk on topics...

[JulianEdgar]

Originally Posted by Vekke

If you have the better way to do these shapes show and tell us how your basic shapes should be used with some samples to get better results?.

Again I havent seen any information to prove your points. Its that simple. At the moment you are too misleading if there is no results or exaples shown.

Also I would appreciate if you could answer my previous questions as this is a forum where we talk on topics...

The whole idea that 'basic shapes' (let alone 'the template') can guide us in the following is just absurd:

- Show where there is separated and attached flow on existing cars
- Guide the shape of rear extensions
- Show how rear spoilers on sedans should be positioned and shaped
- Allow the assessment of the ‘aerodynamic purity’ of cars

Maybe you should read some current aero textbooks, or do some proper on-road testing, to find that out for yourself?

Even the first in the above list ("the template will show us where there is separated and attached flow on existing cars") can be disproved in a few hours of tuft testing - as I showed in the video.

Seriously, we've (I hope) moved beyond blind faith in incantations.

[JulianEdgar]

In fact, why don't we all stop stuffing around and actually go to the most recent, authoritative and up to date reference on car aero - and quote all the mentions (that it does not have) to 'the template'?

That could save a lot of time, couldn't it?



Oh, of course, it's all wrong too....

[ME_Andy]

Google Scholar shows 34 papers including "Hucho", "aerodynamic", and "template" since 2010. Not bad! I wish I had so many citations.

https://scholar.google.com/scholar?q...10&as_yhi=2020

The top one looks really interesting, "Learning three-dimensional flow for interactive aerodynamic design".

https://core.ac.uk/download/pdf/268224768.pdf

"Addressing this problem, our shape representation is based on deforming a template mesh."

[AeroMcAeroFace]

"Addressing this problem, our shape representation is based on deforming a template mesh."

Please don't take quotes out of context, the full quote is included here if you don't have access to the article

"However, it is difficult to discretize volumetric fields consistently
with such a grid-less point-based discretization.
Addressing this problem, our shape representation is based on
deforming a template mesh. While Umetani [2017] deforms a cube
surface to parameterize a 3D shape, we further extend this approach
by deforming a PolyCube. The PolyCube approach allows us to parameterize a wider variation of shapes"

I don't see how in any way that is relevant to this debate.

I will provide a brief article summary below

The authors state that instead of deforming a cube as a starting template for parameterisation of a 3D model, they could use a polycube, essentially many cubes and deforming those using a machine learning algorithm and Gaussian processes to create a 3D model for CFD analysis.

Please only quote things you understand, otherwise things can get taken out of context or misinformation occurs.

[ME_Andy]

LOL. I'm done here.

[freebeard]

LOL. I'm done here.

When it's just getting interesting?

Polycube
A polycube is a solid figure formed by joining one or more equal cubes face to face. Polycubes are the three-dimensional analogues of the planar polyominoes.Wikipedia

This supposedly authoritative book uses geometry that's on the level of Minecraft.

Meanwhile Blender has Adaptive Subdivision, support for OpenVDB and is adding, in alpha, a node-based modifier stack.

Proof again that books lag 6 months or more behind free and Open Source software.

[ksa8907]

Originally Posted by freebeard

Try all caps.

This here, this man wins