NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Feasibility of an Accurate Dynamic Standard for Water Flow
Published
Author(s)
Iosif I. Shinder, Michael R. Moldover
Abstract
We used NIST's primary water flow standard to study the feasibility of accurately determining mass flow rates mdot of water "dynamically," that is from the time derivative of the weight W of the collection tank: mdot,dynamic = (dW/dt)/g. When data for a constant flow in the range 10 kg/s < mdot < 60 kg/s was averaged over 40 seconds, the average dynamic flow rate <mdot,dynamic>, agreed with the static standard within the noise, (<mdot,dynamic>/mdot,static – 1) = 0.00015{plus or minus}0.00033. (The uncertainty is the standard deviation of one measurement). These results are consistent with arguments that dW/dt is only weakly sensitive to jet entering the collection tank and to the turbulence inside the tank. We conclude that further study of a dynamic flow standard for larger flows is justified. A dynamic standard can use a conventional diverter that is much simpler than the uni-directional diverter with collector/bypass unit that was designed and built for NIST's primary, static standard.
Shinder, I.
and Moldover, M.
(2010),
Feasibility of an Accurate Dynamic Standard for Water Flow, Flow Measurement and Instrumentation, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=832344
(Accessed October 1, 2025)