Tuesday, December 31, 2013

Winter Holiday Visit to Colorado

Sara and I went to Colorado to visit family over the winter holidays, and stayed in the little town of Ouray for a few days, which is a lovely place, if not a little quiet during the winter. One thing that we've noted with all of our travels is that we're absolutely spoiled for food in Portland; the food scene in Portland is very good quality food for not all that much money.

Our travels took us to Gunnison, and Crested Butte, and it was full of nice, quiet, family time. More photos here.

Sunday, December 1, 2013

Does drinking from a snifter really matter?

For advanced fluid mechanics, we were assigned a pretty open-ended project, basically to find some neat fluid phenomenon and to photograph and explain it to the best of our abilities. Ondrej and I chose to analyze a snifter glass to see if there is really a reason people should be drinking from them, or if it is just tradition.

The theory behind snifters is that they will allow you to smell your whiskey better. You take your hand, cup the glass, and by virtue of your body heat, heat up the whiskey (no ice, please). This increases the rate of evaporation of the alcohol, which is the primary transit method of the aroma via whiskey congeners, which are responsible for the oak and other smells.

I was responsible for the gaseous stage analysis - what happens to the fluid flow once evaporation has happened. I started with the cylindrical Navier-Stokes equations and continuity, made a bunch of assumptions and boundary conditions, and started simplifying. What finally popped out at the end was a familiar equation for pipe flow, and I threw in a little twist to account for the angle of the snifter walls.

So, as you can see, the flow really is governed by the pressure gradient, and the glass geometry acts as a converging nozzle, just as expected. A fun little analysis, one that intuitively makes sense, but now at least I have the math to back it up. Here is a link to the presentation.