Turbulent thermal convection in wide horizontal fluid layers

Adrian, Ronald J.; Ferreira, Rogerio Tadeu da Silva; Boberg, T.C.

doi:10.1007/bf00280263

Cited by 160 publications

(96 citation statements)

References 47 publications

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“…For unstable conditions (Figure 4c), a large asymmetry is noted. Qualitatively, this asymmetry is similar to the laboratory study of turbulent convection by Adrian et al [1986] and is attributed to the enhanced upward transport of heat due to the bursting thermal plumes near the surface. As the thermal plumes move upward, the temperature of the plume decreases as it mixes with the surrounding cold air and produces the ramp-like pattern noted in Figure 1a.…”

Section: Joint Pdf Of Vertical Velocity and Temperaturesupporting

confidence: 79%

Probability density functions of turbulent velocity and temperature in the atmospheric surface layer

Chu¹,

Parlange

Katul

et al. 1996

Water Resources Research

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Abstract. The probability density functions (pdf's) for the longitudinal and vertical velocities, temperature, their derivatives, and momentum and sensible heat fluxes were measured in the atmospheric surface layer for a wide range of atmospheric stability conditions. The measured pdf's for both the velocity and the temperature fluctuations are near-Gaussian and consistent with corresponding laboratory measurements for nearneutral and stable stability conditions. Hence the first-and second-order moments are sufficient to predict the heat and momentum flux pdf's. The lower-order moments can be estimated from mean meteorological conditions using surface layer similarity theory. For unstable conditions the pdf for temperature is non-Gaussian and is strongly skewed due to local convective thermal plumes. For near-neutral and stable conditions the pdf's for the velocity and temperature longitudinal gradients have long exponential tails, in agreement with findings in laboratory experiments and numerical simulations.

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Section: Joint Pdf Of Vertical Velocity and Temperaturesupporting

confidence: 79%

Probability density functions of turbulent velocity and temperature in the atmospheric surface layer

Chu¹,

Parlange

Katul

et al. 1996

Water Resources Research

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“…while Kiamal and Finnigan (1994) quoting Caughey and Palmer (1979) and Adrian et al (1986) suggest a constant of 0.35. They also quote Hunt et al (1988) for w 2 :…”

Section: Mixed Layermentioning

confidence: 99%

A Wind-Tunnel Artificially-Thickened Simulated Weakly Unstable Atmospheric Boundary Layer

Hancock

Zhang

Hayden

2013

Boundary-Layer Meteorol

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A wind-tunnel simulation of an atmospheric boundary layer, artificially thickened as is often used in neutral flow wind-loading studies, has been investigated for weakly unstable stratification, including the effect of an overlying inversion. Rather than using a uniform inlet temperature profile, the inlet profile was adjusted iteratively by using measured downstream profiles. It was found that three cycles are sufficient for there to be no significant further change in profiles of temperature and other quantities. Development to nearly horizontally-homogeneous flow took a longer distance than in the neutral case because the simulated layer was deeper and therefore the length scales larger. Comparisons show first-order and second-order moments quantities are substantially larger than given by 'standard forms' in the mixed layer but are close in the surface layer. Modified functions, obtained by matching one to the other, are suggested that amount to an interpolation in the mixed layer between the strongly unstable and the weakly unstable cases.

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“…Normally, heating from the bottom and sides of the cup causes thermal convection, which promotes mixing of the fluid inside, and results in a uniform temperature field [9][10][11][12][13]. Therefore, the magnitude of the thermal convection is a key to understanding the temperature fields in the cup and the accuracy of the viscosity measurement in the vibrational viscometer.…”

Section: Introductionmentioning

confidence: 99%

Effect of Thermal Convection on Viscosity Measurement in Vibrational Viscometer

Akpek¹,

Youn²,

Maeda³

et al. 2014

JFCMV

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This paper describes the experimental study of viscosity measurement error in the vibrational type viscometer, which measures viscous damping of the oscillating circular plate in a fluid in continuously increasing temperatures. The experiments are carried out to measure non-uniformity of the temperature field in the test cup of the vibrational viscometer in continuously increasing temperatures, while changing the viscosity of the target fluids. Experimental outcomes show that non-uniformity of the temperature grows in the cup and results in viscosity measurement error, when the viscosity of the fluid increases. In order to understand this phenomenon, velocity measurement by particle image velocimetry is conducted in the test cup for fluids of varying viscosity. The results indicate that mixing is enhanced in the low-viscosity fluid by the occurrence of unsteady thermal convection, while weaker convection appears in the high-viscosity fluid.

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Turbulent thermal convection in wide horizontal fluid layers

Cited by 160 publications

References 47 publications

Probability density functions of turbulent velocity and temperature in the atmospheric surface layer

Probability density functions of turbulent velocity and temperature in the atmospheric surface layer

A Wind-Tunnel Artificially-Thickened Simulated Weakly Unstable Atmospheric Boundary Layer

Effect of Thermal Convection on Viscosity Measurement in Vibrational Viscometer

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