Water tunnel with dye 'smoke lines' for Hot Wheels or 1:24 models?

[Big time]

How to create fine and well defined dye lines in a small water tunnel for Hot Wheels or 1:24 sized models?
Said dye lines would be akin to smoke lines in a wind tunnel.

Also how to fit small scales to measure drag and lift/downforce without having water leaking out or water ruining the scales on such small water tunnels?

[some_other_dave]

#1: Use thin metal wires and run current through them. They'll dissociate the H2 from the O in the water and make bubbles, which will travel with the water.

#2: Invert the model, and make the top of the tunnel the ground. Gravity will keep the water from leaking out any holes in the top.

Make sure you keep open flames away, though.

-soD

[freebeard]

http://ecomodder.com/forum/showthrea...ies-31047.html

EM member graysgarage has documented that which some_other_dave suggests.

[Sven7]

Water is incompressible, and therefore might give you misleading results.

But if you want to, I say just slip a water balloon over the model and clamp the opening real tightly.

[aerohead]

Originally Posted by Big time

How to create fine and well defined dye lines in a small water tunnel for Hot Wheels or 1:24 sized models?
Said dye lines would be akin to smoke lines in a wind tunnel.

Also how to fit small scales to measure drag and lift/downforce without having water leaking out or water ruining the scales on such small water tunnels?

Texas Tech used food coloring,injected through hypodermic needle flush ports on the models surface,fed through very small Tygon tubing, run up through the tunnel floor and then the model's tires.
As the water became cloudy,chlorine bleach was injected to clear it back up.
For drag,the model ran on the floor of a water tank,connected to a sting,which was connected to an overhead rolling bridge which spanned the tank, riding rails.
They used a 3/8th scale model ($68,000),considered the minimum scale to reflect all the details of the actual car.

[freebeard]

Originally Posted by Sven7

Water is incompressible, and therefore might give you misleading results.

vs

Originally Posted by aerohead

As to compressibility,air is considered an incompressible fluid below about 250-mph,as a vehicle would be entering transonic flow in ground-effect.

http://ecomodder.com/forum/showthread.php/beetle-inspired-aerodynamic-thoughts-14070-5.html#post188768

[aerohead]

Originally Posted by freebeard

vs

http://ecomodder.com/forum/showthread.php/beetle-inspired-aerodynamic-thoughts-14070-5.html#post188768

Below transonic velocity,air is regarded as an incompressible fluid,so water is fine for testing low speed aerodynamics (which is a branch of fluid mechanics).
Same-same!

[freebeard]

That's what you said.