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현재 위치

Reynolds number

작성자 Uploader : ezcivil 작성일 Upload Date: 2016-05-10변경일 Update Date: 2016-05-10조회수 View : 709

In fluid mechanics, the Reynolds number (Re) is a dimensionless quantity that is used to help predict similar flow patterns in different fluid flow situations. The concept was introduced by George Gabriel Stokes in 1851, but the Reynolds number is named after Osborne Reynolds (1842?1912), who popularized its use in 1883.

The Reynolds number is defined as the ratio of inertial forces to viscous forces and consequently quantifies the relative importance of these two types of forces for given flow conditions. Reynolds numbers frequently arise when performing scaling of fluid dynamics problems, and as such can be used to determine dynamic similitude between two different cases of fluid flow. They are also used to characterize different flow regimes within a similar fluid, such as laminar or turbulent flow:

* laminar flow occurs at low Reynolds numbers, where viscous forces are dominant, and is characterized by smooth, constant fluid motion;
* turbulent flow occurs at high Reynolds numbers and is dominated by inertial forces, which tend to produce chaotic eddies, vortices and other flow instabilities.

Re = inertial forces / viscous force = ρvL / μ = vL / ν
v : maximum velocity of the object relative to the fluid (m/s)
L : characteristic linear dimension, (travelled length of the fluid; hydraulic diameter when dealing withe river system) (m)
μ: dynamic viscosity of the fluid (N*s/m^2)
ν: nu, kinematic viscosity (ν= μ/ρ) (m^2/s)
ρ: density of the fluid (kg/m^3)

*** 참고문헌[References] ***

https://en.wikipedia.org/wiki/Reynolds_number

Re = v*L/ν


변수명 Variable	변수값 Value	변 수 설 명 Description of the variable

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현재 위치

Reynolds number

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