CBE 30355 - Lecture Notes - December 4, 2014

Announcements

Class notes

The main points of the lecture were

• Turbulence

Goals:

• Determine the characteristic length scale of the viscous sublayer in turbulent pipe flow.
• Estimate the magnitude of the eddy viscosity.

Reading

• The class notes.
• BS&L, chapter 5

Additional Readings:

An interesting example of boundary layer separation, turbulence, and angular momentum is the design of a frisbee. Basically, the angular momentum produced by the spin of the frisbee (and the weighted edges) keeps the frisbee stable (constant orientation) while the aerodynamic lift produced by its motion relative to the air keeps it up. Boundary layer control is important too: The ridges around the edge of the frisbee promote turbulence and delay boundary layer separation, reducing drag. The first frisbees tended to be unstable and didn't fly terribly well. It wasn't until the mid-60's that the frisbee as we now know it was developed. The patent on the ridges can be found here.

Demonstration: