Flow Viz

[Hardingfv32]

Where do you buy Flow Viz?

Any clue how it may be formulated?

Why is fluorescent powder used?

Brian

[Mike Allison]

Gary Eaker, designer and owner of the AeroDYN Wind Tunnel (www.aerodynwindtunnel.com) is known in NASCAR as the Wind Wizard. He can probably answer your questions and more. Try geaker@aerodynwindtunnel.com

Tell him I sent you. Mike Allison

[Brands]

You can make flow vis solution out of almost anything really. I've even used a mix of brake cleaner, T Cut polish and monkey butt powder! It worked really well. The 'proper' recipe is the flourescent powder (which shows up really well in UV light), parafin (not sure what you guys call that over here) and a dash Oleic acid which acts as an anti coagulant. Slap it on the underside of a wing (or anywhere you like) and run the car (or wind tunnel). The parafin will evaporate leaving the powder to show you how bad your wing is stalling!

[Frank C]

British "paraffin" is kerosene. The advantage of kerosene over oil in wind tunnel testing is that it eventually evaporates, leaving the pigment behind. Pictures can be taken after the fact with the tunnel off or the car stopped. One does have to worry about the effects of gravity on the paint in regions with low shear stress - does the paint follow the flow or run down because of gravity or is it a vector combination? A cheap readily available pigment (a little coarse, but acceptable) is Crayola Powder Paint - just go to Hobby Lobby, etc.
- Frank C

[AJWALKER]

We mixed flourescent powder with Aeroquip assembly lube (like stp) and thin slighty with gear oil depending on surface. You can also get flourescent dyes at NAPA that mix with oil or water. Add some ivory soap/water wetter and inject at speed from plastic syringe through hypo tube on surface of interest. have fun.

[brownslane]

I have used WD 40 for thirty years. At least while testing, it mixes enough with the dust off the track to provide great tracings. And it is light enough to move everywhere, even into lower pressure areas.

An added benefit is that any wings I have used it on have never squeaked
Tom