water monitoring

There's no direct connection. A large number of extremely small particles can cause as much turbidity as a smaller number of larger particles because the amount of light passing through the water is similarly dispersed.

And to make things murkier you can have a Surface Scatter Turbidimeter or a Subsurface Turbidimeter which will read differently when used on the same liquid sample. Its a funny science.

Rok

Wikipedia: http://en.wikipedia.org/wiki/Nephelometric_Turbidity_Unit

Water on the web: http://waterontheweb.org/under/waterquality/turbidity.html

NTU is a very general rough scale, that does not really tell much.

Agreed.

There is not any connection between size of particles and NTU. Number of particles is more connected, if particles exist.

Hi, noyz and nicolafluid!

Welcome to both of you. Hope you continue to contribute and have fun in CR4. Great to have both of you in here; and I'm looking forward to enjoying your shared thoughts/opinions in future blogs!

Interesting question, both from and about "Noise" in the flow. This blog is a macro example of turbulence using the answers you have received thus far.

• The conduit is the subject matter of "turbulent flow"; and
• the flow restriction is the OP (original posting).
• The fluid is the responses you have encouraged to pass through the conduit past your restriction.
• Through it now, you have seen longer and shorter, and more or less complicated responses.
• The turbulence may only be measured in terms of the contents together with any complexities placed upon them (just the physical equivalents alone might include velocity, viscosity, density, specific gravity, compoundedness, state of matter, etc. etc.).

In addition, the measurements you are trying to achieve are affected by the turbidity metering device itself, which presents other considerations in determining a measurement.

As Wikipedia points out when examining the effectiveness of one variety of turbidity measuring device, "To some extent, how much light reflects for a given density of particles is dependent upon properties of the particles such as their shape, color, and reflectivity. Therefore, establishing a working correlation between turbidity and suspended solids (a more useful, but typically more difficult quantification of particulates) must be established independently for each situation." They might well have added "...and how the measuring beam of light and/or reflectivity is affected by those qualities..." to include such things as beam concentration, colour, pulse rate, intensity, etc. etc. in the list of variables attributed to this particular measuring device.

For practical purposes, the state of turbidity of a constant substance at a constant flow rate through one restriction only is calculated as a constant after a couple of measurements to reassure the measurer of a certain mean of turbulent flow at that point.

Or, unless you are testing the restriction device itself to provide e.g. marketing data, you can just use a standard 'rule of thumb' rate drop of 1 per restriction.

Mark

Agreed. I am producer of W.treatment systems, and often use the NTU measurement in situ. It tells me overall (very overall) condition of systems. After consideration of foults, other measurements should be provided. (TDS, SS, granulometry etc).

Glad to chat with you all.

Nikolafluid