Origin of the temperature oscillation in turbulent thermal convection.
We report an experimental study of the three-dimensional spatial structure of the low-frequency temperature oscillations in a cylindrical Rayleigh-Bénard convection cell. Through simultaneous multipoint temperature measurements it is found that, contrary to the popular scenario, thermal plumes are emitted neither periodically nor alternately, but randomly and continuously, from the top and bottom plates. We further identify a new flow mode-the sloshing mode of the large-scale circulation (LSC). This sloshing mode, together with the torsional mode of the LSC, are found to be the origin of the oscillation of the temperature field.
Xi
Heng-Dong
HD
Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
Zhou
Sheng-Qi
SQ
Zhou
Quan
Q
Chan
Tak-Shing
TS
Xia
Ke-Qing
KQ