Onset of coherent oscillations in turbulent Rayleigh-Bénard convection.
We report temperature cross correlation and velocity profile measurements in the aspect-ratio-one convection cell filled with water. A sharp transition from a random chaotic state to a correlated turbulent state of finite coherence time is found when the Rayleigh number becomes larger than a critical value Ra(c) approximately equal to 5 x 10(7). The experiment reveals a unique mechanism for the onset of coherent oscillations in turbulent Rayleigh-Bénard convection.
Qiu
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Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
Tong
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