Recent Velocity Measurements in Turbulent Thermal Convection
Recent velocity measurements in turbulent thermal convection in water are presented. With the newly developed techniques of single-beam and dual-beam cross-correlation spectroscopies, local-velocity fluctuations in the central region of the convection cell and the mean velocity profile near the boundary are measured at various Rayleigh number Ra ranging from 107 to 1011. The experiment reveals new scaling laws in the velocity statistics and the boundary layer properties. The novel convection experiment carried out in a cell with rough upper and lower surfaces shows an enhanced heat transport, which provides new insights into the roles of the thermal plumes played in determining the transport of heat across the cell.
KeywordsCombustion Convection Coherence Posite Pyramid
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