i am reserching airodynamic drag for a physics project and i keep finding references to reynolds number, the laws state that for reynolds number greater than 1000, use quadratic form and for reynolds number less than 1 use the liniar form. can anyone explane to me:
what is reynolds number?
how is it calculater?
what hapens for reynolds number between 1 and 1000?
this is a question to do with fluid dynamics
The Reynolds number NR is proportional to the ratio of inertial forces (those required to accelerate the medium) to those of viscous drag.
The first goes as v^2, because the work done in accelerating the medium goes as (1/2)rho.v^2. The viscous drag is proportional to v.
At low speed and in high viscosity media, viscous forces are large and the flow is laminar. At high speed and in low viscosity, the medium is accelerated substantially.
At high values of NR, one gets turbulence. At low values, laminar flow. The value at which turbulence starts depends on the geometry and even with given geometry is uncertain, as it depends on history. It is typically at values of order 1000.
There is an article on Wikipedia
http://en.wikipedia.org/wiki/Reynolds_number
Joe
Joe
The first goes as v^2, because the work done in accelerating the medium goes as (1/2)rho.v^2. The viscous drag is proportional to v.
At low speed and in high viscosity media, viscous forces are large and the flow is laminar. At high speed and in low viscosity, the medium is accelerated substantially.
At high values of NR, one gets turbulence. At low values, laminar flow. The value at which turbulence starts depends on the geometry and even with given geometry is uncertain, as it depends on history. It is typically at values of order 1000.
There is an article on Wikipedia
http://en.wikipedia.org/wiki/Reynolds_number
Joe
Joe