Goddamnit. “The fact that you can stir water ….” (Not “store water”)
Goddamned spell-changer does not work with a 12-inch screen and eyes that no longer work. > On Aug 5, 2023, at 11:38 AM, David Eric Smith <desm...@santafe.edu> wrote: > > I think you have several variables in play at the same time here, Nick, and > that will make it challenging to get clear what-all is involved, and what is > controlling in what combinations. > > 0. Let me say something general, which won’t be comprehensible within this > bullet, but which I will unpack a little in a later one. I _expect_ that for > some fairly symmetric shapes like soda bottles or sinks and drain pipes or > whatever, under constant atmospheric conditions etc., water of properties > that doesn’t change while it flows (not clear this applies to dishwashing > remnant water with soap foams and scums), and so forth, there would be some > unique steady state that was the true dynamical state the system would settle > into over a sufficiently long time. The simplest set of questions you could > try to ask about would be the properties of that steady state: what it does > as a transport process; what boundary conditions it depends on, etc. What > that means is, no bifurcations into several possible, but distinct, > indefinitely long-persisting steady flow conditions. Give me that expectation > for now, so I can make another point. Proving when it applies will be some > nightmare of going into details, which I probably couldn’t do, certainly > don’t have time and patience to try, and probably couldn’t put into English > even if I could do it. From that one question, everything else gets harder > because more dimensions come into play. In particular, there could a whole > continuous parameter range of long-lived transients, which decay toward the > long-term steady state only very slowly. Your problem as a dishwasher or > bottle tilter is: you may not have as long to wait as it takes those > transients to decay. It’s Keynses “in the long run, we are all dead” > (Strictly: that was the point he was making.) > > 1. So at the least, the fact that you can store the water before pulling the > plug, and affect the drain time, means you can put different amounts of > angular momentum into the water that cannot get transferred out fully, fast > enough to not leave an imprint on the draining. Since the only way to get > down the drain is to first get _to_ the drain, if you put enough angular > momentum into the water, it makes it harder for any of it to get to the > center. Why (among other factors) hurricane eyes don’t close. So indeed, > you can stir in a way that gives the water slower access to the drain, and > causes it to take longer to all get through it. > > 2. There is a different issue of closed versus open. The reason the soda > bottles mouth-to-mouth are so useful is that the only way water can go down > is if air goes up. But the bottles are small enough that for air to bubble > up through the water requires getting through enough surface tension that it > significantly affects the draining. Having “enough” vortex to obviate that > need then speeds your drainage. But with the soda bottles too, if you spun > them continuously, to keep introducing angular momentum to the water faster > than it could transfer away toward the steady state by dissipation, I think > it is sure you can affect the drainage. I suspect the shape of the soda > bottles is such that angular momentum equalizes toward the steady state more > quickly. A sink with a flat bottom should be very hard, because you can put > in tons of angular momentum that doesn’t get quickly reflected back. (Also, > square or round perimeter and bowl shape of the sink, how full is it relative > to width, and other such things. It can get as complicated as billiards (not > really, but figuratively), if you consider all the momentum reflecting > around.). > > 3. The hard thing to do in emails or posts, and which really will require > some computer program in the general case, is to figure out how gravity — in > the infinitely long term — interacts with pressure and wall friction to > resupply angular momentum to maintain a steady-state vortex, for a given > vessel shape, mouth width, etc. > > The question of when you can make a universalizing claim, such as “symmetry > breaking (like adding a rotation) will certainly increase or decrease a > downward flow”, remains an important one, and many of us have daily instances > of that problem in one or another area (ecological dynamics, physiology > versus natural selection in populations, and on and on). So, good to have > ongoing interest. The amount one has to say to have spoken carefully, to > figure out what categories are coherent for which to try to generate answers, > remains striking (at least to me). > > Eric > > > >> On Aug 5, 2023, at 11:05 AM, Nicholas Thompson <thompnicks...@gmail.com> >> wrote: >> >> Ok, folks. I apologize to those of you who are fed up with my kitchen >> physics, but there has been a bit of a development in that saga that I want >> to share with those few of you who aren’t. Years ago, I came home for the >> summer with my ears ringing with the notion that structures are formed to >> dissipate gradients. Please set aside any teleological implications of this >> statement and ask the question in its most neutral form: Do the structures >> that sometimes form as a gradient is dissipated dissipate it more quickly >> once the structure has been formed. Or, as I came to interpret it, does >> facilitating the formation of such a structure speed the dissipation of the >> gradient. >> >> I was the family dishwasher at the time. I deplore washing dishes, but I >> love messing around with warm soapy water, and so I started to experiment >> with starting the vortex that forms after you pull the plug out of the sink >> before I pulled the plug. Quickly, it became apparent that facilitating the >> vortex formation in that way GREATLY SLOWED the emptying of the sink. >> Triumphally, I wrote Steve on Friam only to be greeted by a torrent of >> scatological raillery, so intense and so persistent from the fluid >> dynamicists on the list that I never heard from Steve. The burden of this >> raillery I have distilled into Roberts Rule of Order: DEFROCKED ENGLISH >> MAJORS SHOULD NOT BE ALLOWED TO TALK about fluid dynamics. >> >> More than a decade later, I am back in Massachusetts, washing dishes at the >> same sink, and the question occurred to me again. I raised it finally with >> Steve, and he generously sent me the little two-bottle toy, where you flip >> it over and the water drains from one bottle to the other. As it drains, it >> forms a vortex in the draining bottle, and the occurrence of the vortex >> greatly increases the speed of the draining. Finally, if one facilitates >> the formation of the vortex by rotating the bottle a bit, the bottle drains >> even more quickly. Thus, the result is entirely different, especially if >> one substitutes two large pop bottles for the ones included in the kit. >> >> At the risk of bringing another round of raillery down on my head, I opine >> that the difference has something to do with the fact that two bottle >> situation is more of a closed system than the sink situation. The test >> would be to saw the bottom off both bottles and demonstrate that >> vortex-formation now slows drainage. >> >> It will be a while, though, before I can get two extra bottles to destroy. >> >> Does anybody care to make a prediction and offer an explanation why the >> results should be different in the two cases? >> >> Nick >> >> -. --- - / ...- .- .-.. .. -.. / -- --- .-. ... . / -.-. --- -.. . >> FRIAM Applied Complexity Group listserv >> Fridays 9a-12p Friday St. Johns Cafe / Thursdays 9a-12p Zoom >> https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fbit.ly%2fvirtualfriam&c=E,1,loAvj02q-QGxD1j9yZ2GhJdCFLU5wXofg1CrZWDyPUaW4J_n1unbai3jZwaOChQ6Oxz7d5MC89E-WQd2Js3yRNNOFGbC2ja-Y3shOc2_aLeuRG9O00GbZTB9hBbW&typo=1 >> to (un)subscribe >> https://linkprotect.cudasvc.com/url?a=http%3a%2f%2fredfish.com%2fmailman%2flistinfo%2ffriam_redfish.com&c=E,1,6pwtuRXDhgsRm7oxxIGJIhcy87jIomiy1mnpkFP_dClxVq7ygsXfH6fuVwnKJfAAQ1Ub8Y2wAx3diygaS6SigPKh7JO9kLZ0UfctOw8jRdM,&typo=1 >> FRIAM-COMIC >> https://linkprotect.cudasvc.com/url?a=http%3a%2f%2ffriam-comic.blogspot.com%2f&c=E,1,ukRcywbdET9No0m3u7sJE_RkL304ocQvrJCZg07dtO5xO92vxzZ7KQnWUFaBuhglth6pL7y4duTBwDYJHBywoJdQamrqd2SHkQu3rxHt99kaFYtfOXvK&typo=1 >> archives: 5/2017 thru present >> https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fredfish.com%2fpipermail%2ffriam_redfish.com%2f&c=E,1,GuSKG5cEyMTuj8-f7LJqIW2yZO6Hj0BXXl7YEPwnuEMbhji5RgY8SgJIfumBC0s52k9_ttL9iVJr_lPlS6b5yjH53FZKSH-x3tccJvVj&typo=1 >> 1/2003 thru 6/2021 http://friam.383.s1.nabble.com/ >
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