Anatomy of a laminar starting thermal plume at high Prandtl number

Davaille, Anne; Limare, Angela; Touitou, F.; Kumagai, Ichiro; Vatteville, Judith

doi:10.1007/s00348-010-0924-y

Cited by 44 publications

(33 citation statements)

References 45 publications

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“…We derive the plume height from the tracer fields; y p is defined as the highest point at which the local tracers originated from below the PIV domain (y  1.39 mm). This was found to be consistent with the definitions based on the maxima of f (Cagney et al, 2015) and the gradient of the radial velocity (Davaille et al, 2011), but contained less scatter. The rise velocity signal, u r (t), was then found by di↵erentiating y p (t) using the least-squares method.…”

Section: The Vortex Ring Bubblesupporting

confidence: 76%

Constraining the source of mantle plumes

Cagney

Crameri

Newsome

et al. 2016

Earth and Planetary Science Letters

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In order to link the geochemical signature of hot spot basalts to Earth's deep interior, it is first necessary to understand how plumes sample di↵erent regions of the mantle. Here, we investigate the relative amounts of deep and shallow mantle material that are entrained by an ascending plume and constrain its source region. The plumes are generated in a viscous syrup using an isolated heater for a range of Rayleigh numbers. The velocity fields are measured using stereoscopic Particle-Image Velocimetry, and the concept of the 'vortex ring bubble' is used to provide an objective definition of the plume geometry. Using this plume geometry, the plume composition can be analysed in terms of the proportion of material that has been entrained from di↵erent depths. We show that the plume composition can be well described using a simple empirical relationship, which depends only on a single parameter, the sampling coe cient, s c . High-s c plumes are composed of material which originated from very deep in the fluid domain, while low-s c plumes contain material entrained from a range of depths. The analysis is also used to show that the geometry of the plume can be described using a similarity solution, in agreement with previous studies. Finally, numerical simulations are used to vary both the Rayleigh number and viscosity contrast independently. The simulations allow us to predict the value of the sampling coe cient for mantle plumes; we find that as a plume reaches the lithosphere, 90% of its composition has been derived from the lowermost 260 750 km in the mantle, and negligible amounts are derived from the shallow half of the lower mantle. This result implies that isotope geochemistry cannot provide direct information about this un-sampled region, and that the various known geochemical reservoirs must lie in the deepest few hundred kilometres of the mantle.

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Section: The Vortex Ring Bubblesupporting

confidence: 76%

Constraining the source of mantle plumes

Cagney

Crameri

Newsome

et al. 2016

Earth and Planetary Science Letters

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“…Legendre series with orders N = [6,7,8,9,10,12,15,20] are used. The virtual beam mesh is three time finer than the pixel grid.…”

Section: Tests On 8-bits Noiseless Imagementioning

confidence: 99%

“…15a shows an image (inverted and with enhanced contrast) of a laminar thermal plume. This experimental study was designed to better understand convection in the Earth's mantle [37,10]. The experiment consists of a tank filled with sugar sirup and containing a heating cylinder device at its bottom.…”

Section: Fiber Transported By a Fluid Flow In A Fracturementioning

confidence: 99%

“…According to the beam theory [8], the curvature is of importance as it is related to the bending moment. In fluid mechanics [9][10][11][12], or chemistry, the line to be identified can be a front (temperature, concentration...). In this case, the knowledge of the normal vectors, related to the angles of tangents, can be needed for a flux computation.…”

Section: Introductionmentioning

confidence: 99%

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Accurate measurement of curvilinear shapes by Virtual Image Correlation

Semin

Auradou

François

2011

Eur. Phys. J. Appl. Phys.

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Abstract. The proposed method allows the detection and the measurement, in the sense of metrology, of smooth elongated curvilinear shapes. Such measurements are required in many fields of physics, for example: mechanical engineering, biology or medicine (deflection of beams, fibers or filaments), fluid mechanics or chemistry (detection of fronts). Contrary to actual methods, the result is given in an analytical form of class C ∞ (and not a finite set of locations or pixels) thus curvatures and slopes, often of great interest in science, are given with good confidence. The proposed Virtual Image Correlation (VIC) method uses a virtual beam, an image which consists in a lateral expansion of the curve with a bell-shaped gray level. This figure is deformed until it fits the best the physical image with a method issued from the Digital Image Correlation method in use in solid mechanics. The precision of the identification is studied in a benchmark and successfully compared to two state of the art methods. Three practical examples are given: a bar bending under its own weight, a thin fiber transported by a flow within a fracture and a thermal front. The first allows a comparison with theoretical solution, the second shows the ability of the method to deal with complex shapes and crossings and the third deals with ill-defined image.

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“…The application of optical diagnostics to convective flows is due to the particular importance of convection in geodynamics, atmos-pheric and oceanic physics, hydrodynamic and thermal processes with phase transitions, etc. Experimental studies of a plume gener-ated by a suddenly switched-on point [6] or linear source [7] have shown that the results of determination of the dynamics and shape of convective structures depend on the visualization method used. The velocity field of the visualized phase structure [8] in the liquid may differ significantly from the velocity field measured using particle image velocimetry [9] or laser Doppler velocimetry [10].…”

Section: Introductionmentioning

confidence: 99%

Hilbert diagnostics of convective structures and phase transition in super cooled water

Dubnishchev¹,

Арбузов²,

Arbuzov³

et al. 2018

IJET

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The evolution of the crystallization wave front and convective structures in a horizontal layer of supercooled water bounded by temperature-controlled flat surfaces is visualized using methods of Hilbert optics. The phase transition is manifested by the occurrence of a crystallization wave and is accompanied by a positive energy release, which, in turn, affects the dynamic distribution of the optical phase density gradient in supercooled water and induces phase perturbations in the probing light field. The results of measurements of the phase velocity and the shape of the crystallization front approximated by Bezier curves are presented. The wave front velocity is obtained using modified time-of-fight method. The phase velocity field is found to exhibit spatio-temporal quasi-periodicity that can be related to the existence of oscillatory phenomena in the crystallization process.

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Anatomy of a laminar starting thermal plume at high Prandtl number

Cited by 44 publications

References 45 publications

Constraining the source of mantle plumes

Constraining the source of mantle plumes

Accurate measurement of curvilinear shapes by Virtual Image Correlation

Hilbert diagnostics of convective structures and phase transition in super cooled water

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