In all cases, there was no significant variation in current speed over the 10 minute experimental period (ANOVA test, = 0.05). An value of 0.05 was used throughout to calculate confidence intervals and to determine significance via Student t-tests.
The stream appeared to have a stable, smooth flow, with some evidence of large-scale vorticity. In the vertical dimension (y-displacement) there was measurable movement of particles with net up and down displacement at discrete points in the channel. Since z-displacement (across the channel) was not measured, it was not possible to measure vorticity directly.
With one pump and a constant channel width of 5 cm, mean current velocity 4-5 cm above the bottom was 0.253 ± 0.006 m/s. Mean vertical displacement velocity was 0.010 ± 0.002 m/s.
With one pump and a constant channel width of 5 cm, mean current velocity 3-4 cm above the bottom was 0.258 ± 0.005 m/s. Mean vertical displacement velocity was 0.010 ± 0.002 m/s.
There was no significant difference in current speed or vertical displacement velocity between the 3-4 and 4-5 cm zones.
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