You need this software before dimples work

[Logic]

Sal Rodriguez a nuclear engineer at Sandia National Labs came up with software where you input:
1: Your shape. (eg: car body)
2: The 'fluid' (air) its moving through.
3: The speed at which its moving through the 'fluid'
And it outputs the optimal ...er... 'Dimplage' for your car etc for you!

eg:
The so dimpled nose cone of a rocket averaged 22% less frictional drag. (peak: 39.1%)

https://www.sandia.gov/labnews/2024/...ple-at-a-time/

https://www.asme.org/topics-resource...nks-to-dimples

This is most likely the software the dimpled piston crowd (linked below) got their grubby mits on!
https://ecomodder.com/forum/showthre...omy-41382.html

I would guess that said software would be much sought after here.
I have not (yet) found such and doubt if Sandia puts it up for download all over their site,

[freebeard]

He shouldn't be hard to find:

https://www.sandia.gov › labnews › 2023 › 09 › 07 › sandian-named-scientist-of-the-year
Sandian named Scientist of the Year - LabNews
Sep 7, 2023 DYNAMIC ROCKET — Sal Rodriguez showing the dimpled rocket he helped create as part of a 2022 fluid dynamics project with the University of New Mexico. (Photo by Jennifer Plante) Great Minds in STEM, which recognizes America's top engineers and scientists from the Hispanic

Mebbe AI could reverse engineer the algorithm by analyzing produced examples? Dimples might be augmented by corrugations and tuburcles.

[Piotrsko]

Suspect poking dimples is faster/easier than other techniques. AI should be able to use either if it's as good as speculated. I have my doubts that commercial is as good as the pro stuff.

[aerohead]

I looked all the links. Here are some observations:
1) Sal's rocket, at 470-mph, would be governed by transonic flow, and shockwave drag, in comparison to road vehicles, governed by pressure drag due to flow separation ( the SPACE-X Dragon system experiences highest drag at 'Max-Q', with a vehicle of 135-sq-ft frontal area, @ an altitude of about 52,800-feet, negative 70-F, velocity of 1,000-mph, and air density @ about 15% that of air at sea level ).
2) Sal writes that his method is good for 'any fluid', but then he walks it back with the caveat, ' so long as it's turbulent.'
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3) Road vehicles are not designed for 'turbulent' air.
4) Sal reports that Al Unser Jr.'s Mustang ( and I'm presuming that he's referring to a NASCAR Cup, race car ) demonstrated a minimum, 25% drag reduction.
5) At 200-mph, the Mustang's aerodynamic road load is on the order of 540.1-horsepower.
* Surface friction drag power absorption is approx. 36-horsepower ( 6.6% of total )
* Pressure and induced-drag power absorption is approx. 504.1-horsepower ( 93.3% of total ).
* It's hard to reconcile a total drag reduction of 25%, via reduced surface friction drag, when it was less than 7% to begin with.
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6) The Mustang is 193.4-inches in length ( 16.1-feet ).
7) The Mustang is 78.6-inches in width ( 6.55-feet ).
8) The 'top' of the Mustang has approx. 105.5-sq-ft of surface area, compared to an overall wetted surface area of approx. 220-sq-ft.
9) If 'dimpling' the hood impacted the entire 'top' of the car, this would constitute 47.7% of total surface area, or, 3.17% of total drag.
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10) At 3.17-mph, the Mustang begins transitioning from laminar boundary-layer ( LBL ), to turbulent boundary-layer ( TBL ).
11) By 10-mph, Reynolds number is over 1.5-million, with full TBL, and the Mustang's drag coefficient is essentially 'fixed', with the exception of variable wheel ventilation drag, up to 250-mph.
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12) With TBL, and in a most favorable pressure gradient, there's no issue with 'attached' flow over the hood/bonnet, as the TBL is moving from 'high' to 'low' pressure ( Bernoulli Theorem ). As far as attachment ( which is the most critical criteria for 'aerodynamics') the flow doesn't require any 'help'.
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13) Since no data is presented from:
* Gene Haas Racing Wind Tunnel, North Carolina
* Automotive Center for Excellence ( ACE ) Wind Tunnel, Oshawa, Canada
* (Stellantis ) Chrysler Aero Acoustic Wind Tunnel, Michigan
it may be that the drag data presented, is from the CFD evaluations done by Graham Monroe, at The University of New Mexico. If so, we have no data with regards to the software used ( Exa POWERFLOW, and SIEMENS Star CCM+ would be the only 'industry-quality' CFD in existence at the time ).
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Perhaps there'll be additional reporting, with higher specificity in the future.

[freebeard]

3) Road vehicles are not designed for 'turbulent' air.

Road vehicles operate in the 6 foot deep micro-climate at the ground surface. Isn't that by definition turbulent?

[Piotrsko]

Yes that flow would be turbulent but the object running through that is independent and could be, (but probably wont) laminar. Tis why there is an undefined transition zone in Reynolds Numbers

[aerohead]

Originally Posted by freebeard

Road vehicles operate in the 6 foot deep micro-climate at the ground surface. Isn't that by definition turbulent?

I'm not acquainted with the term.
There's no mention of it in any extant technical publications, regarding road vehicle aerodynamics.
Earth does have it's own boundary layer which ranges from 500-m thickness, to 300-m thickness, depending on whether 'urban' or 'rural', or in between, but its not 'constant.' We discussed this here decades ago.
This summer. we'll have the 'Dog Days' in which there's no wind, no turbulence.
Any way you slice it though, automobiles are not 'designed' with atmospheric 'turbulence' in mind. Things are what they are, we have no control over what we'll experience from one day to another, so we just live with what we get.
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The 'TURBULENCE' of interest to us is, the turbulence behind regions of flow separation around an automobile's body.
This turbulence is pure entropy. None of it's kinetic energy can ever be converted to pressure recovery.
The entire premise of road vehicle 'aerodynamics' is the reduction, or complete elimination of flow separation.
PhD or not, I believe that Sal Rodriguez has conflated the drag reduction potential of 'dimples', and will come to realize it as more empirical testing proceeds.

[freebeard]

It's a term of art in architectural practice.

Microclimate
A microclimate is a local set of atmospheric conditions that differ from those in the surrounding areas, often slightly but sometimes substantially. The term may refer to areas as small as a few square meters or smaller or as large as many square kilometers. Because climate is statistical, which implies spatial and temporal variation of the mean values of the describing parameters, within a region there can occur and persist over time sets of statistically distinct conditions, that is, microclimates. Microclimates can be found in most places but are most pronounced in topographically dynamic zones such as mountainous areas, islands, and coastal areas. Wikipedia