Velocity Estimate from Schlieren Flow Visualization

[jagadeeshr]

Hi,

I recently came across a blog on schlieren visualization.

I replicated it with the following: Convex lens (130 mm dia and 350 mm focal length), LED light source (5 mm white LED) and smartphone camera (Moto G4 Plus).

Flow visualization of a hair dryer can be seen here.

Can anyone suggest how to estimate the velocity of the air flow?

Thank you
Jagadeesh R

 

[3DDave]

Good looking job. I don't believe that this flow visualization is so good for velocity estimation. In sonic and super sonic flow one can see the angle of the shockwave, but for low velocity flow you mostly see the effects of turbulence.

In cases where it is really important to know there are a lot of techniques.

Check these videos - I'm sorry and don't have a complete index to get exactly to what you might want, but they are all worthwhile if you have an interest. I would probably start with Flow Visualization. These are from a while ago. More recent techniques such as laser doppler measurement and hot wire anemometers can also be used.