In article , BR says...

All this just to have the ability to repeat the rotary motions in case a
particular fluid
pattern interests me.

I built a setup like this years ago, we used a large custom
built rectangular tank, and there were various types of
paddles run by a Bodine variable speed motor, which
oscillated vertically up and down.

The fish-flake solution (that what the visualization
fluid is actually made of, BTW) was used to watch the
flow dynamics for various paddle shapes and speeds.

Later they fitted a laser doppler velocimeter to the
setup to get three-axis velocity profiles.

Jim

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