9/19/2023 0 Comments Kinematic viscosity![]() ![]() These viscometers wet the timing section of the viscometer capillary only during the actual measurement and must be cleaned, dried and refilled before a repeat measurement can be made. The Cannon®-Fenske Opaque, Cross Arm, and BS/IP/RF U-Tube viscometers have been designed for testing opaque liquids. Other suspended level viscometers in this catalog include the BS/IP/SL, BP/IP/SL(S), and BP/IP/MSL viscometers. Unlike the Cannon®-Fenske Routine viscometer, suspended level viscometers maintain the same viscometer constant at all temperatures, which is advantageous when samples are to be measured at different temperatures. ![]() The Ubbelohde viscometer and other suspended-level viscometers are used to measure transparent liquids. Other viscometers for transparent samples in this catalog include the Cross Arm and BS/U-Tube viscometers. The Cannon®-Fenske Routine viscometer is a rugged and inexpensive viscometer that works well if the sample is transparent or translucent. Please refer to the following brief descriptions for determining which viscometer is best suited for your particular application. Each viscometer is supplied with a calibration certificate, and holders should be ordered separately. All types of viscometers conform to ASTM D446 and related standard specifications for glass capillary kinematic viscometers. Koehler offers a full selection of glass capillary viscometers for measuring kinematic viscosity of liquid petroleum products in accordance with ASTM D445 and related standard test methods. Unitless numbers occur very frequently in fluid mechanics.Calibrated Glass Capillary Kinematic Viscometers So when you calculate $Re = s L / \nu$, you come out with a pure number that has no units. Note that is the same units as kinematic viscosity. We could have just kept the original two quantities.Īs for the units, the other two quantities in the reynold's number equation are length and velocity. Now it's 3 equations, exactly 1 of which has to do with the type of fluid, and 2 that have to do with the particular situation. ![]() Because it comes up so often, and because both density and viscosity are intrinsic to the type of fluid, we simplify the Reynold's number equation to just $Re = s L / \nu$, where $\nu$ is kinematic viscosity. The reynold's number is super important and it comes up all the time in fluid mechanics. Of these four quantities, 2 are intrinsic to a particular fluid (density and dynamic viscosity) and 2 are more to do with the situation (the length and the velocity). The Reynold's number is defined as $Re = \rho s L / \mu$, where $\rho$ is density, $s$ is velocity, L is a length, and $\mu$ is dynamic viscosity. Flows with high reynolds number will behave completely differently than flows with low reynolds number. One of the fundamental distinctions has to do with the ratio of inertia forces to viscous forces, which is called the Reynold's number. To understand what it is, you have to understand that there are many different types of fluid flow, and they behave very differently. Thinking of it as so many $m^2$ of fluid flowing per second is not what it is about. Don't try to think of it as resistance of fluid to flowing, because that's not what it is. Kinematic viscosity is something totally different. honey has much higher dynamic viscosity than water, or cold motor oil has higher dynamic viscosity than warm motor oil. High dynamic viscosity = more resistance to flow. This is what lay people think of when they think viscosity. Dynamic viscosity represents the resistance of fluid to shear forces as you said. ![]()
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