This automation industry quiz question comes from the ISA Certified Control Systems Technician (CCST) program. Certified Control System Technicians calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables. Click this link for more information about the CCST program.
The Reynolds Number for a flowing fluid is most affected by which of the following parameters?
c) friction factor
e) none of the above
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The Reynolds Number for a flowing fluid can be generalized as the ratio of kinetic (or inertial) forces divided by viscous forces. Although friction factor and temperature do affect inertial forces and viscosity to some degree, and therefore, Reynolds number, viscosity has the most direct effect upon the value of the Reynolds Number.
The correct answer is A, “viscosity.”
Reference: Goettsche, L.D. (Editor), Maintenance of Instruments and Systems, 2nd Edition