Cheg 355 - Lecture Notes - Nov. 16, 2004
Announcements
Class notes
Scanned Notes
The main points of the lecture were
Goals:
After this class you should be able to:
- Scale the transport equations to determine the length scale appropriate in a boundary layer, and develop the Prandtl boundary layer equations.
Reading
- The class notes.
- BS&L, chapter 4
- Multi-Media Fluid Mechanics: Work through Boundary Layers: Boundary Layer Concepts.
Additional Readings:
Boundary layer flows lead to fascinating phenomena. One key problem in flow
past a bluff body at high Re is boundary layer separation, and the transient wakes
which form behind the body. These vortices often become detatched from the object
leading to what is called a von Karman Vortex Street. As the eddies are shed from
alternate sides of the body, there are often large lateral forces exerted on the body. If
the frequency of the Karman eddy shedding matches a resonant vibrational frequency
of the object - watch out! To see a brief discussion (and a little movie) of the vortex
shedding process, go
here.
To see a classic example of what happens when the frequency hits resonance, check out
one of many websites on the Tacoma Narrows bridge disaster. One good one may be
found
here.
Demonstration:
Propagation of a Toroidal Vortex
Homework Exercises (Due Nov. 23, 2004)
problem set 10
solution
David.T.Leighton.1@nd.edu