Question
The mu(I) (“myoo-one”) rheology describes the flow of these systems in a similar manner to that of complex fluids. For 10 points each:
[10m] In the Brazil nut effect, large particles tend to rise up through what systems? They are composed of many small macroscopic particles.
ANSWER: granular systems [or granular flows; prompt on grains; prompt on examples of granular systems, such as sand]
[10e] The Brazil nut effect is often called the granular version of this process, in which density or temperature differences cause motion via “currents” or “cells” within a fluid.
ANSWER: convection [or word forms of convecting; accept granular convection or convection currents or convection cells]
[10h] In a 2008 paper, Rietz and Stannarius studied granular convection for low values of this number, which exceeds one for a supercritical flow. It equals velocity over the square root of the product of little g and a length scale.
ANSWER: Froude (“frood”) number [or Fr]
<Physics>
Summary
| 2024 ACF Nationals | 2024-04-21 | Y | 24 | 9.58 | 83% | 8% | 4% |
Data
| Berkeley B | Cornell B | 0 | 10 | 0 | 10 |
| Minnesota B | Chicago C | 0 | 10 | 0 | 10 |
| Chicago D | McGill | 0 | 0 | 0 | 0 |
| Claremont Colleges | Toronto B | 0 | 10 | 0 | 10 |
| Columbia B | Arizona State | 0 | 10 | 0 | 10 |
| Duke | Ottawa | 0 | 0 | 0 | 0 |
| Yale B | Florida | 0 | 10 | 0 | 10 |
| Georgia Tech | Berkeley A | 0 | 10 | 10 | 20 |
| Vanderbilt | Harvard | 0 | 0 | 0 | 0 |
| Chicago A | Indiana | 0 | 10 | 0 | 10 |
| Iowa State | Maryland | 0 | 10 | 0 | 10 |
| Johns Hopkins | Northwestern | 0 | 10 | 0 | 10 |
| Truman State | Kentucky | 0 | 0 | 0 | 0 |
| Michigan | Illinois | 0 | 10 | 0 | 10 |
| Chicago B | Minnesota A | 0 | 10 | 0 | 10 |
| NYU | Brown | 0 | 10 | 0 | 10 |
| North Carolina A | Purdue | 10 | 10 | 0 | 20 |
| North Carolina B | South Carolina | 0 | 10 | 0 | 10 |
| Penn | Rutgers | 0 | 10 | 0 | 10 |
| WUSTL A | Stanford | 0 | 10 | 0 | 10 |
| Cornell A | Texas | 0 | 10 | 0 | 10 |
| Virginia | WUSTL B | 0 | 10 | 0 | 10 |
| Waterloo | Columbia A | 10 | 10 | 0 | 20 |
| Yale A | Toronto A | 0 | 10 | 0 | 10 |