#### Characteristics of a Boundary Layer over a Flat Surface: Screencast

Describes a boundary layer

We suggest that after watching this screencast, you list the important points as a way to increase retention.

##### Important Equations:

\[\dot{\gamma} = \frac{\partial v}{\partial x} + \frac{\partial u}{\partial y}\]

where \(\dot{\gamma}\) is the shear rate of the fluid (units of 1/s) and \(u\) and \(v\) are the horizontal and vertical components of velocity (m/s).

\[\tau = \mu\, \dot{\gamma}\]

where \(\tau\) is the shear stress acting on the fluid (units of N/m^{2} = Pa) and \(\mu\) is the dynamic viscosity (units of Pa-s)

\[Re_x = \frac{\rho\, U_{\infty}\, x}{\mu}\]

where \(Re_x\) is the Reynold’s number (dimensionless, with the coordinate \(x\) as the length scale), \(\rho\) is the density of the fluid (kg/m^{3}), and \(U_{\infty}\) is the speed of the fluid flowing far away from the surface (m/s).