rickman wrote in :

You are aware that a standing wave still moves up and down, no? So a
trough turns into a crest and vice versa.


I've seen waves on water in a tank that don;t. You can see them in the
laminar flow froma tap set low, as the stream hits the ceramic. Totally
static...

About the other thing, I put it badly, but imaguine a tank brim-full. Now
imagine a static half-wave, convex, supported by the sides with walls
extended up from the tank (I didn't mention that before, stupidly). Now I'm
not even sure that ONE halfwave can be static, convex, maybe it can only be
stable concave due to gravity. I really don't know. I was just thining that
if statiuc convex IS possible, then once set up, the edns of the takk have
water reaching them below the brim, ergo you could chuck a bit more water in
to top it up. Hence storage. Same (likely dubuious) logic as a flyhweel,
in that to store extra anagery you can either rasie speed for fixed mass, or
raise mass for fixed speed. If it's recirpocal, then an ability to add mass
to that tank seemed to indicate storage capability being raised.

There may well be a flaw in all that, but I'm expressing it as best I can.