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Another version of this course (I think it was an OCW version on YouTube.) had a video of a fish holding position in a stream. There was an obstacle in the stre
by theothermkn 8y ago
Another version of this course (I think it was an OCW version on YouTube.) had a video of a fish holding position in a stream. There was an obstacle in the stream, and the fish swam up into its wake to save energy. Neat. Then they showed a video of a dead fish being towed through a simulated stream by a line. It exhibited "swimming" behavior that could be dismissed as just flapping in the current right up until the dead fish swam up into the lee of the nearby obstacle for shelter.
It's amazing how much adaptation and complex behavior can be embedded into an underactuated system. A fish's dead body "knows" how to save energy when swimming against a current!
- jeffreyrogers 8y agoYep, that's an amazing video. The course is being taught this semester and is being livestreamed and recorded on YouTube. I think the 5th lecture is tomorrow. Videos from previous semesters are also on YouTube.
- colanderman 8y agoI'm curious the results of that experiment with a towed sphere. My gut says it too would find the lee, simply because that's a local and stable energetically favorable configuration of the system.
- CorpDrone0123 8y agoI think this might be the video you mention: https://vimeo.com/44887922 https://vimeo.com/44887922 - interesting stuff.
- carapace 8y agoI can't find a link right now, but a dead whale will move forward at a knot or two just due to the action of its flukes in the waves. Some folks were working on a means to propel boats by artificial flukes.