

@mastersthesis {7067,
	title = {Thermal dissipation field and its statistical properties in turbulent {Rayleigh}-{Benard} convection},
	year = {2009},
	note = {3398675},
	school = {Hong Kong University of Science and Technology (Hong Kong)},
	type = {phdPh.{D}.},
	address = {Ann Arbor},
	abstract = {A systematic study of the thermal dissipation field and its statistical properties is carried out in turbulent Rayleigh-B{\'e}nard convection. A local temperature gradient probe consisting of four identical thermistors is made to measure the normalized thermal dissipation rate ε N (r ) in two convection cells filled with water. The measurements are conducted over varying Rayleigh numbers Ra (8.9{\texttimes}10 8 <= Ra <= 9.3{\texttimes}109 ) and spatial positions r across the entire cell. It is found that εN ( r ) contains two contributions; one is generated by thermal plumes, present mainly in the plume-dominated bulk region, and decreases with increasing Ra. The other contribution comes from the mean temperature gradient, being concentrated in the thermal boundary layers, and increases with Ra. From the measured instantaneous thermal dissipation rate ε N (r , t ), we construct a locally averaged thermal dissipation rate ετ ( r , t ) over a time interval τ and study the τ-dependence of the moments, [left angle bracket][Special characters omitted.] (r , t )[right angle bracket]t , averaged over time t. A good scaling regime, in which [left angle bracket]([Special characters omitted.] )p [right angle bracket] goes as [left angle bracket]([Special characters omitted.] )p [right angle bracket]\~{}[Special characters omitted.] for all values of p up to 8, is found for all three dissipation contributions ετ (r , t ) (i = x, y, z ). The obtained exponents μi (p ) at three representative locations in the convection cell are explained by a phenomenological model, which combines the effects of both buoyancy for velocity statistics and geometric shape of the most dissipative structures in turbulent convection. The experiment thus provides a complete physical picture about the thermal dissipation field and its statistical properties in turbulent convection.},
	keywords = {0794:Materials science, Applied sciences, Materials science, Rayleigh-Benard convection, Thermal dissipation, Thermistors, Turbulent convection},
	url = {http://search.proquest.com/docview/251365409?accountid=14270},
	author = {He, Xiaozhou}
}
