[FRIAM] Off the wall question about turbulence

Steve Smith sasmyth at swcp.com
Tue Nov 28 12:54:31 EST 2023

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 

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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