Monday, December 13, 2010

Slip-Sliding Away

While you may first think that this will be an entry about the massive snow storm that struck town on Saturday (even when it is light and fluffy, 17.1 official inches of snow is a lot of snow - the fifth largest snowfall on record and enough to collapse the roof of the Metrodome (video) [*]), this is actually about wall slip occurring at the solid boundaries of flow fields.

Richard Buscall has a letter to the editor published in the latest Journal of Rheology (subscription required or pay-per-view) that made a salient point or two regarding slip. My favorite quote was regarding the use of roughened or serrated tools in rheometers.
The author once heard somebody accused of neglecting slip say 'Yes, I am aware of the possibility of slip but did not want to compromise the accuracy with which the gap was set and quantified.' Now, one can be sure that that person did not actually mean 'I was prepared to risk the possibility of an error of unknown and therefore arbitrarily large magnitude in order to avoid the uncertainty in the gap setting of, perhaps, 1%'. Except that is what their assertion amounted to."
I always love the way the British are able to insult in such an incisive manner.

[*] Even though we all know that it was Brett Farve who did it just because he wanted another day to recover from his injuries.


Eric F. Brown said...

So, since you've lost your football team for the week, do the Twin Cities feel like Omaha? ( ) NB: inside blog joke.

John said...

"...and Dr. Brown scores big with that one! Here comes his famous Nebraska-Knee-Knocking Nutbush dance and the crowd goes wild!!!"

It looks like this weekend's game might be played at the University's stadium, which is both a) ironic, since the Gophers used to play in the Metrodome, and b) appropriate as the Vikings are only playing at a college level this year.