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Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.
where k is the reduced frequency, and A is amplitude of the heaving oscillation. Strouhal number (Sr) as a function of the Reynolds number (R) for the flow past a long circular cylinder. For large Strouhal numbers (order of 1), viscosity dominates fluid flow, resulting in a collective oscillating movement of the fluid "plug".
The Knudsen number is a dimensionless number defined as =, where = mean free path [L 1], = representative physical length scale [L 1].. The representative length scale considered, , may correspond to various physical traits of a system, but most commonly relates to a gap length over which thermal transport or mass transport occurs through a gas phase.
fluid mechanics, geology (ratio of grain collision stresses to viscous fluid stresses in flow of a granular material such as grain and sand) [7] Bejan number (fluid mechanics) Be = fluid mechanics (dimensionless pressure drop along a channel) [8] Bejan number (thermodynamics) Be
The conversion factor k was chosen so that the values for C were the same as in the Chézy formula for the typical hydraulic slope of S=0.001. [9] The value of k is 0.001 −0.04. [10] Typical C factors used in design, which take into account some increase in roughness as pipe ages are as follows: [11]
A simplified version of the definition is: The k v factor of a valve indicates "The water flow in m 3 /h, at a pressure drop across the valve of 1 kgf/cm 2 when the valve is completely open. The complete definition also says that the flow medium must have a density of 1000 kg/m 3 and a kinematic viscosity of 10 −6 m 2 /s , e.g. water.
A Newtonian fluid is a power-law fluid with a behaviour index of 1, where the shear stress is directly proportional to the shear rate: = These fluids have a constant viscosity, μ, across all shear rates and include many of the most common fluids, such as water, most aqueous solutions, oils, corn syrup, glycerine, air and other gases.
Pressure and temperature sensors providing pulses can be used to determine mass flow, with division of the pulses by the K-factor, or multiplication with the inverse of the K-factor providing factored totalization, and rate indication. Furthermore, by dividing the pulse rate by the K-Factor, the volumetric throughput per unit time of the rate ...