Saturday, March 23, 2013

Incrementally implementing the semi-impossible.

We're closing in on final design for our Emflume -- a "desktop flume" for undergrad students in engineering, fisheries, and geology -- giving them hands-on understanding of fluid mechanics. 

Our flume will demonstrate things like fish passage through culverts -- real-world hydraulics problems.  Nothing like it exists, but needs to, so we're doing it.

Making this portable, affordable, practical flume is not easy -- that's why nobody's done it yet.

Instrumentation is another challenge.  A laser Doppler velocimeter, at around $40K, could give us water velocity, but we need something cheaper.

I'm working with colleagues -- thanks Chris Krumm, who needs no linkage -- to measure velocity in new ways.  Like measuring heat loss from a heated probe.

Ever been cold in a freezing wind?  Wind chill.  Works that way.

Here's a short movie showing work we did today -- using another method, a "drag body," to measure velocity.  And video analysis of particle movement and turbulence in the flume.

Crude stuff; here it is.

During my research on fluid velocity measurement, specifically thermal anemometers, I found an amazing website, by Johan Liljencrants, who worked on sound and speech and electronics at the Royal Academy of Sweden.  

He used thermal anemometry to measure air flow in pipe organs.

Johan died last year.  I wish I had known him, and heard much more of his research on sound and pipe organs, but honor him here, and by using sound from one of his pipe organs in my movie.


matt kuchta said...

Very cool! This is the kind of thing the high speed camera was built for.

Steve Gough said...

Yes indeed, Matt. We're working on the drag body because it's cheap and effective, also can be used to teach about drag in fluid mechanics. Fortunately, we're able to borrow a nice flow meter for calibration; I was using the camera here to get ballpark velocity values and look at turbulence.

crinkles said...

The music is fantastic! It illustrates well the meticulousness of your flume trials.
Water looks amazing in slo-mo!