[FRIAM] Off the wall question about turbulence

[glen]

A friend of mine was doing "anomaly detection" using vibration sensors. I'm not sure he told me the actual context. But all the examples we talked about were in finely tuned things like bearings. The idea was that you could attach a sensor fairly far way, then use machine learning to classify the vibrations to match any proper modes of the machine ... and complementarily detect non-proper modes. (What is this called? when you induce the common stuff so you can detect the uncommon stuff too rare to induce directly? "latent induction"?) It all depends on the fidelity of the propagation of the signal from the site to the sensor. And you couldn't (I'm guessing) have many mechanisms in between the target mechanism(s) (on the critical path) versus those you may not care much about ... biasing overtones, I guess.

I feel confident there are a couple of people on this list that might be able to say whether one could distinguish the ... [ahem] ... acoustic emission of turbulence from that of perhaps non-laminar but benign flow like I imagine happens in a trap under intermittent use.

On 11/28/23 09:54, Steve Smith wrote:
> I like the "listening" ideation offered, I *have* used the temperature/tactility mode of holding my hand on a P-Trap to "feel" how the water flows... vibrations convolved with "coolth"...  usually filling the sink partway and holding the p-trap in my hand while I pull the plug and "feeling" for warm/cool spots and vibrations implying flow patterns.
> 
> Very hard to calibrate, very intuitional and maybe just a ritual to go through while I wait for my intuition (or the lye-based organic-gunk-dissolver to do it's work if/when I use such a thing) to catch up with the things I can imagine measuring overtly...   I have not put in nearly the requisite canonical 10,000 hours unclogging drains but I'm much better at intuiting what they need after 60 years of practice than I was say 5 or 10 years into a lifetime of recalcitrant drains.
> 
> Toilets are nothing more in some ways than a p-trap themselves and they generally do exhibit vorticity when they flush (well). When fighting a recalcitrant toilet,  one of the first hints I have that the plug hasn't fully abated is that no vortex forms, even if the water level does subside (slowly)...      I believe (but have not verified) that the water-flow *into* the bowl is designed to promote vorticity while the bulk of the work is the *suction) caused by an abrupt overflow of the column of water leaving the back of the toilet's built-in P-trap?
> 
> On 11/28/23 7:01 AM, glen wrote:
>> My intuition was "of course there's turbulence in the trap" ...
>>
>> I was going to suggest you unhook the washer, have a friend pour water from a large bucket into the drain while you hold your ear, tightly, to the side of the u-trap ... or maybe clamp your teeth on it so you can hear vibration that way ... or use a hose clamp to mount a rod and clamp your teeth onto that rod ...
>>
>> Or, you could use a piezo sensor:
>> https://www.circuits-diy.com/piezoelectric-vibration-sensor-module/
>> I'm not sure what turbulence in the trap might sound like. But you won't know until you take the data.
>>
>> You could also get one of those fancy snakes with a camera on the tip ... way more fun than taking apart the pipe.
>>
>> On 11/27/23 09:22, cody dooderson wrote:
>>> I have no idea. You might be able to buy a clear plasti replacement for the u-trap. Then you could add some food coloring to the wash and record a video of what happens.
>>>
>>> _ Cody Smith _
>>> cody at simtable.com <mailto:cody at simtable.com>
>>>
>>>
>>> On Mon, Nov 27, 2023 at 7:42 AM Prof David West <profwest at fastmail.fm <mailto:profwest at fastmail.fm>> wrote:
>>>
>>>     When the washer drains, water flows for a bit, then you hear the pipe filling up and water comes out the top. Pause the flow, water drains quickly, start and pipe fills again. Cycle till rate of flow subsides.
>>>
>>>     Question: can turbulence occur at the u-trap and cause a temporary blockage?  If yes, does the  turbulence occur because of the distance from entry to the u-trap?
>>>
>>>     Will ask plumber — but prior discussions of turbulence on the list made me think it might pose an interesting problem..


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