Fish Scales reduce drag 25%

[donpearsall]

Here is a great article that researchers have found that fish scales reduce drag 25% vs a smooth surface.

Evidently the overlapping fish scales reduce drag by causing a zig-zag motion of the water:
"Professor Bruecker's team has discovered that the fish-scale array produces a zig-zag motion of fluid in overlapping regions of the surface of the fish, which in turn causes periodic velocity modulation and a streaky flow that can eliminate Tollmien-Schlichting wave induced transition to reduce skin friction drag by more than 25 percent."


Fish are low-speed of course, but the aerodynamicists think this could apply to high speed aircraft.

https://phys.org/news/2020-10-aerodynamicists-reveal-link-fish-scales.html

Someone try this on an LSR car and tell us the results!

Don

[jacksoni]

With the exception of Comp Coupe where streamlining is allowed, I think this would run afoul of rule 4.CC. Would try in a wind tunnel first and for sure before spending bunch of money (if the above suggested did indicate a benefit) get a formal answer from SCTA if going to one of their meets. JMHO

[WOODY@DDLLC]

Jack, wouldn't an orange peel paint job do the same thing and still be legal? 

[jacksoni]

Hmmmm. Well I think an orange peel paint job runs afoul of rule # 2.K Appearance in that all vehicles......present a neat appearance...... LOL  Nice try. 

[drmayf]

Certainly an interesting thought. As to rules violations, seems to me that it would be no worse than adding small vortex generators to control the flow around a vehicle.   There are a lot of factors to consider and one is of dynamic similitude or dimensional analysis. While the thought seems reasonable when you start comparing water flow to air flow and the different densities in the fluids and the and the vastly different speed associated, it  would need to be computationally addressed. I suspect that the scale of the fish body, those with scales probably don't work for higher speeds. No proof but suspect something like that. For instance, why do sharks  have no scales? Sharks a damned fast in the water for the size and very energy efficient. Once you folk do the dimensional analysis then do some trading fact work to determine the cost benefit of making the changes.  Might find that fast means really small scales (barracuda goes fast but aren't their scales pretty small. Heck since we are supposing, why not just take a ballpein hammer and dimple the vehicle all over  like a golf ball.

Anyhoo,  all ya'll have fun figuring it out! i think you might find it rather difficult to design such a drag reducing system. Why not active boundary layer control?  Or dang, just add more turbo boost... cheaper...

drmayf TWFS

[jacksoni]

With great respect to Dr Mayf, "small vortex generators" are illegal too....(except where streamlining is allowed=/CC)

[Stan Back]

Most people don't realize that all species of sharks are naturally turbocharged.  I saw that fact on the intranet.

[gowing]

With great respect to Dr Mayf, "small vortex generators" are illegal too....(except where streamlining is allowed=/CC)

Quoted from the article:
"Their surprising research outcome runs counter to the common belief that roughness promotes by-pass transition. Instead, the scales largely increase the stability of the base flow similar to an array of vortex generators."

similar to is not the same as,... so maybe it would be legal?

[Stan Back]

Let's not restrict streamlining just to Competition Coupes.  I believe it's allowed in S classes, too.

[aircap]

Lots of salt racers run flat black. Why not wrinkle paint? Or better yet - cover the car with truck bed coating.

Didn't Petty run a vinyl roof on one of his racers because the engineers thought it added a mile or two to the top end? I know NASCAR tech suspected it, and off came the vinyl.

[wobblywalrus]

How many mph will I get from this?

[Jack Gifford]

I had no idea that we ought to try eliminating the Tollmien-Schlichter wave-induced transition.

[wobblywalrus]

Most fish are coated with a layer of slime that gives them a smooth surface over the scales.

[Lemming Motors]

I have an idea that one of the Americas Cup Yachts had some special surface coating a while back but then again, those teams can afford to buy up tons of fish; what adhesive would you use to stick the scales on with; I bet they gave that job to the apprentice; man this job stinks 

[desotoman]

How many mph will I get from this?

I have an idea that one of the Americas Cup Yachts had some special surface coating a while back but then again, those teams can afford to buy up tons of fish; what adhesive would you use to stick the scales on with; I bet they gave that job to the apprentice; man this job stinks 

Thanks, great way to start the morning with a hearty laugh. 

Tom G.