The Power of the Waves

Jospa Blog

August 25, 2009

Comments on the chuter and the video

Filed under: Uncategorized — admin @ 6:38 pm

The chuter - see picture - has side walls held apart at the front by a piece of wood (brown colour). It has no bottom, and water and air are fed in to it ONLY above the ‘knife’ level. The oscillation of the chuter can be adjusted - see picture of the pivot mechanism.

The video - listen to comments and watch for the meniscus of water in the chuter from about 00.15 to 00.32 seconds on the track. The next view shows a flotation collar being used and the final view is of the output end of the tube.chuter-pivot5

The chuter

Test to assess ability of “chuter” to feed air and water

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Readers of the progress of the ITC will be aware that the principle of the waves moving the water and air along inside the tubes seems to work well, but we hadn’t found a reliable unaided way to feed the air and water into the tube. This was a critical requirement and previous attempts were not successful.

The “chuter”

So we designed and made what we call a “chuter” -a new word that we made up from chute[1].

The chuter has arms that capture a wide width of water (wave) and funnel it into a narrower section, in this case a tube. Nothing new here, this is the normal tapered channel in “overtopping” wave technology. Now remember that as waves are propagated the surface of the water looks like it goes up and down, but actually the water molecules move in a circular or oval orbital path to transfer their momentum as seen in the diagram[2].  Most of that momentum is available in the upper portion of the wave.

ChuterOvertoppers have an upward-sloping bottom section which adds to the horizontal channelling of the arms to produce potential energy (overtopping head). In contrast the chuter hasn’t any bottom, but cuts and admits the top 20 - 25% of the wave. The kinetic energy in the rotation is used to maintain the forward momentum of the wave, exactly as required by the ITC.

The chuter is pivoted to give the pitching motion that admits water and air alternately.

The test

In the test we used just 1.2m of tube, so little power was developed: the only objective was to test the infeed (feeding in) of the air and water.

The video shows clearly that this was very successful. The cutting action of the chuter clearly worked as the water jumps into the chuter funnel over the cutting blade. Varying the pivot action has a considerable control of the pitching. Water can be seen to issue from the tube in spurts: naturally the associated air spurts can’t be seen.

Next steps

We shall soon do more chuter tests to help characterise it, and later still some tests with measurements with longer tube to prove the power developed.

We also have an idea for another infeed method that may prove to be even better than the chuter as it may be useful for control by feedback. We have started on its design and hope to test it later.

[1] A chute is a passive (not powered) conveyor section to move fluid goods (normally grain, flour, aggregate, cement) forward by sliding or under gravity. Our “chuter” is to move air and water into the tube.

[2] With thanks to

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