TURBIDITY CURRENTS (Fill & Spill)

Provided by Gary Parker, St. Anthony Falls Hydraulic Laboratory, University of Minnesota.

Time - 2:10 (12.4 MB)

This experiment consisted of a series of turbidity currents, dyed red, white and green. The configuration of the basin is of a fill and spill geometry, where the turbidity current runs into a silled basin beyond which it overflows down into a lower basin floor. Only a few clips are shown.

0:00 &endash; 0:36 &endash; Far out in the basin (below) a white turbidity flow has already taken place and some dilute suspension from that event is still settling. A second flow, dyed red, is just moving into view. In real time you can see the flow head billow up as it moves.

0:36 &endash; 1:19 &endash; A third flow, dyed white, is added to the tank. As it flows into the basin it displaces the turbid red water and a wave of thickened flow moves across the basin. As the flow approaches the sill, it punches through the red cloud of suspended material and crosses the sill (at 1:05). After topping the sill, the flow picks up inertia as it flows down the steeper slope. The flow head billows up as it entrains water during acceleration..

A fourth flow is added, dyed red, but not shown in the movie.

1:20 &endash; 1:54 &endash; A fifth flow, dyed dark green, enters the tank. It moves much like flow #3, however you can more clearly see it mix with the red turbid water of the preceding flow.

1:54 &endash; 2:10 &endash; A view farther down the basin as flow #5 moves across the frame.

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