Editing Boundary layer (section)

== Predicting convective flow conditions at the boundary layer in a cylinder using dimensional analysis ==

By using the convective and viscous force equations at the boundary layer for a cylindrical flow you can predict the convective flow conditions at the boundary layer by finding the dimensionless Reynolds Number (<math> Re </math>).

Convective force: <math>\rho v^2\over\ L </math>

Viscous force: <math>{\mu v\over\delta_2^2} </math>

Setting them equal to each other gives:

:<math> {\rho v^2\over\ L}={\mu v\over\delta_2^2} </math>

Solving for delta gives:

:<math> \delta_2=\sqrt{\mu L\over\rho v} </math>

In dimensionless form:

:<math> {L\over\delta_2}={\sqrt{\rho v L\over\mu}}=\sqrt{Re} </math>

where <math> Re </math> = Reynolds Number; <math> \rho </math> = density; <math> v </math> = velocity; <math> \delta_2 </math> = length of convective boundary layer; <math> \mu </math> = viscosity; <math> L </math> = characteristic length.