I dunno - Bernoulli?

Are we trying to sense instantaneous or max flow?

either way, put a flapper or float device in the channel and have the other end indicate on a scale. (like your speedometer) If it is max you want have it ratchet. Or go electric monitoring and have continuous data.

You're right. You don't know. Hint: if his description is accurate, it's an open channel of constant cross section, therefore constant flow speed and constant static pressure. Which has nothing to do with your drawing or Bernoulli's principle.

A port placed orthogonally to the gutter won't be exposed to dynamic pressure, the only force it will "see" is atmospheric pressure, plus the weight of the water column directly above the port. Regardless of flow rate. He could attach a tube between the test port and the bottom of a glass burette and he would have a real-time indication of level.

Flow would only matter if the test port was oriented directly into the flow vector. If you did that, the total pressure would be the sum of static pressure plus dynamic pressure (flow). Try this picture. The only difference is that the flow path is an enclosed tube, not an open channel:

Attached Thumbnails

 

That pic is incorrect. The pressure is going to be higher on the downstream, reduced dia side.

__________________
Jim

This...

Here's one that measures 0.5 to 5 gallons/minute:

https://pvcpipesupplies.com/f-550-5-5-gpm-50-m-npt-f-55500l.html?gclid=Cj0KCQjw2K3rBRDiARIsAOFSW_7VjwlxZBV7abliaVcOoNTsSrM620txN16Qcvljgv49VFYlIDsfjiAaAi lSEALw_wcB

No pressure gauges needed, just an eyeball or two.

Are you talking about the Bernoulli diagram? It's correct, but not applicable. In a closed system with incompressible fluid, the pressure will be lower and the flow velocity higher where the path is constricted.

If you're talking about the static pressure diagram that I posted, static pressure will be constant along the entire run because the flow path has uniform cross section.

First post said how much water. Another said depth.
Which is it?

Area velocity flow meter: https://greyline.com/index.php/products/water-wastewater/open-channel-flow/avfm-6-1-area-velocity-flow-monitor-132-detail

Tempera paint dries and doesn't get washed off.

I can choose how long the water is running. I can run it for 15 seconds or 15 hours if I wish.

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I recondition w123/w126/w124/w140/r107/r129/ steering boxes!


1984 300D "Elsa" odo reset 6/2011 147k
1983 300TD "Mitzi" ~268k OM603 powered
1995 E300 "Adelheid" 262k [Sold]

I want to know the depth of the water exiting the gutter.

Installing a flapper or other metering device wouldn't give me a measurement I wanted and would interfere with the airflow.

__________________
Onus probandi incumbit ei qui dicit, non ei qui negat

I recondition w123/w126/w124/w140/r107/r129/ steering boxes!


1984 300D "Elsa" odo reset 6/2011 147k
1983 300TD "Mitzi" ~268k OM603 powered
1995 E300 "Adelheid" 262k [Sold]

Both. The amount of water can be measured by the depth exiting the gutter.

As stated elsewhere, I can't accurately collect the water from a specific gutter and calculate the depth.

__________________
Onus probandi incumbit ei qui dicit, non ei qui negat

I recondition w123/w126/w124/w140/r107/r129/ steering boxes!


1984 300D "Elsa" odo reset 6/2011 147k
1983 300TD "Mitzi" ~268k OM603 powered
1995 E300 "Adelheid" 262k [Sold]

Can you see it? mark the side and look at the level. How much flow are we looking at?

how big is this, what sort of depth?

Is the flow relatively constant? I could re ask the same questions you didn't answer ....

http://www.globalw.com/products/wl705.html

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