| Autor: |
Tsuji Y; Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8603, Japan., Mizuno T, Mashiko T, Sano M |
| Jazyk: |
angličtina |
| Zdroj: |
Physical review letters [Phys Rev Lett] 2005 Jan 28; Vol. 94 (3), pp. 034501. Date of Electronic Publication: 2005 Jan 26. |
| DOI: |
10.1103/PhysRevLett.94.034501 |
| Abstrakt: |
The large-scale circulation, often called "wind," in the confined thermal turbulence of mercury is studied experimentally. The instantaneous velocity profile at 128 points is directly measured using ultrasonic velocimetry. The periodic velocity oscillation is observed in the case of the aspect-ratio Gamma = 1,2 but not in Gamma = 0.5. Its peak frequency is scaled by f(c) proportional Ra(gamma(c)), where Ra is the Rayleigh number and gamma(c) = 0.43,0.45 for Gamma = 1,2. f(c) is close to the wind circulation frequency f(p), and has the same order of transit time from the bottom to the top of the convection cell. A single roll circulation is expected in Gamma = 1; however, axisymmetric toroidal rings may exist near the upper and lower plate for Gamma = 0.5, which are stable up to Ra = 7 x 10 (10). |
| Databáze: |
MEDLINE |
| Externí odkaz: |
|
