Gravity currents produced by constant and time varying inflow in a circular cross-section channel: Experiments and theory

Longo, Sandro; Ungarish, Marius; Federico, Vittorio Di; Chiapponi, L.; Addona, Fabio

doi:10.1016/j.advwatres.2016.01.011

Cited by 14 publications

(6 citation statements)

References 20 publications

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“…Fluid velocity in the vertical, radial and azimuthal directions was measured by five ultrasound velocity profilers (UVPs; model DOP 2000, Signal Processing SA, Switzerland) with a carrier frequency of 8 MHz and data rate of 15-20 profiles per second, depending on the set-up. The fluid was seeded with TiO 2 parcels, characterized by high sonic impedance, so that the UVPs could measure their velocity at different distances (gates) along the axis of the ultrasonic cone on the basis of the Doppler shift of the echoes (see Longo et al (2016) for more details). Because the speed of sound depends on the density and temperature of the fluid, the position of the gate and parcel velocity were corrected using the model for density-bulk modulus-salinity suggested by Mackenzie (1981).…”

Section: Methodsmentioning

confidence: 99%

Buoyancy transfer in a two-layer system in steady state. Experiments in a Taylor–Couette cell

Petrolo

Longo

2020

J. Fluid Mech.

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Section: Methodsmentioning

confidence: 99%

Buoyancy transfer in a two-layer system in steady state. Experiments in a Taylor–Couette cell

Petrolo

Longo

2020

J. Fluid Mech.

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“…For example, if Re h 0 /r o = 10 3 the regime Re e > 1 corresponds to V(t)/V(0) > 0.065. This estimate can be applied to inward drainage, by using the gap r o (1 − r i ) instead of r o in (13) and the subsequent uses of Re e . Below, the camera used for the side shot is shown…”

Section: Transition To the Viscous Regimementioning

confidence: 99%

“…The resolution was approximately 0.1 cm pixel −1 , and the overall uncertainty due to parallax errors or grid defects was approximately 0.2 cm. For the partial width gate experiments the height of the current was measured by the image analysis and also by four ultrasound distance meters (US1, US2, US3, US4) (TurkBanner Q45UR), with a data rate of 100 Hz and a nominal accuracy of 0.03 cm, positioned on the top of the tank (see Longo et al [13], for details on these sensors). US1 was positioned 6.8 cm behind the gate, at r = 0.91 (r * = 110.7 cm, θ = 26 • positive counterclockwise, see Fig.…”

Section: The Experimental Layout and Proceduresmentioning

confidence: 99%

Experimental verification of theoretical approaches for radial gravity currents draining from an edge

et al. 2021

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We present an experimental study of inertial gravity currents (GCs) propagating in a cylindrical wedge under different drainage directions (inward/outward), lock-release (full/partial gate width) and geometry (annulus/full cylinder). We investigate the following combinations representative of operational conditions for dam-break flows: (i) inward drainage, annular reservoir, full gate; (ii) outward drainage, full reservoir, full gate; and (iii) outward drainage, full reservoir, partial gate. A single-layer shallow-water (SW) model is used for modelling the first two cases, while a box model interprets the third case; the results of these approximations are referred to as “theoretical”. We performed a first series of experiments with water as ambient fluid and brine as intruding fluid, measuring the time evolution of the volume in the reservoir and the velocity profiles in several sections; in a second series, air was the ambient and water was the intruding fluid. Careful measurements, accompanied by comparisons with the theoretical predictions, were performed for the behaviour of the interface, radial velocity and, most important, the volume decay $${\mathcal {V}}(t)/{\mathcal {V}}(0)$$ V ( t ) / V ( 0 ) . In general, there is good agreement: the theoretical volume decay is more rapid than the measured one, but the discrepancies are a few percent and the agreement improves as the Reynolds number increases. Velocity measurements show a trend correctly reproduced by the SW model, although often a delay is observed and an over- or under-estimation of the peak values. Some experiments were conducted to verify the role of inconsistencies between experimental set-up and model assumptions, considering, for example, the presence or absence of a top lid, wedge angle much less than $$2\pi $$ 2 π , suppression of the viscous corner at the centre, reduction of disturbances in the dynamics of the ambient fluid: all these effects resulted in negligible impacts on the overall error. These experiments provide corroboration to the simple models used for capturing radial drainage flows, and also elucidate some effects (like oscillations of the radial flux) that are beyond the resolution of the models. This holds also for partial width lock-release, where axial symmetry is lost.

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“…2016; Longo et al. 2016). The continuous release of a dense scalar from a moving source has, to the best of our knowledge, never been studied systematically and no canonical configuration exists for the study of the resulting gravity current.…”

Section: Introductionmentioning

confidence: 99%

Gravity currents from moving sources

et al. 2021

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Gravity currents produced by constant and time varying inflow in a circular cross-section channel: Experiments and theory

Cited by 14 publications

References 20 publications

Buoyancy transfer in a two-layer system in steady state. Experiments in a Taylor–Couette cell

Buoyancy transfer in a two-layer system in steady state. Experiments in a Taylor–Couette cell

Experimental verification of theoretical approaches for radial gravity currents draining from an edge

Gravity currents from moving sources

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