An insulating plate drifting over a thermally convecting fluid: the effect of plate size on plate motion, coupling modes and flow structure

Mao, Yadan

doi:10.1017/jfm.2021.192

Cited by 8 publications

(37 citation statements)

References 46 publications

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“…Corresponding to the variation of plate motion, three distinct coupling modes were identified in both two-dimensional (2-D) and 3-D simulation results, namely stagnant mode I (SM I), stagnant mode II (SM II) and unidirectional moving mode (UMM). These three coupling modes are observed for both the Rayleigh number of 10 6 and that of 5 × 10 7 , with the critical plate size for the UMM being smaller for the latter case (Mao 2021). As the thermal blanket effect enhances with plate size, plates of different sizes exhibit distinct behaviour when they encounter a cold downwelling at their leading edge and are subsequently slowed down by the associated impeding flow.…”

Section: Introductionmentioning

confidence: 94%

“…As a result, SM II becomes unstable and the plate soon moves onto one of the cells and terminates its stagnancy. In these cases, the plate is observed to be more stagnant than its neighbouring plumes (Mao 2021). This may appear somewhat counter-intuitive, since common notion held that the continent is normally more mobile than the deep mantle plumes.…”

Section: Introductionmentioning

confidence: 99%

“…The strong thermal blanket effect of the supercontinent soon diminishes the cold downwelling until it vanishes and subsequently nurtures a hot upwelling underneath which generates a divergent horizontal flow that disperses the continents away from the upwelling. Even for cases with a single floating continent, rich dynamic feedbacks are also observed (Gurnis 1988; Zhong & Gurnis 1993; Phillips & Bunge 2005; Whitehead & Behn 2015; Mao, Zhong & Zhang 2019; Mao 2021). An interesting feature captured by these studies is that plate motion seems to vary with plate size: a small plate exhibits relative long durations of stagnancy interrupted by short episodic velocity bursts; whereas a large plate always moves with an appreciable velocity.…”

Section: Introductionmentioning

confidence: 99%

“…Recent studies of Mao et al. (2019) and Mao (2021) focus on details of the variation of plate motion with plate size and the underlying mechanism for it. Corresponding to the variation of plate motion, three distinct coupling modes were identified in both two-dimensional (2-D) and 3-D simulation results, namely stagnant mode I (SM I), stagnant mode II (SM II) and unidirectional moving mode (UMM).…”

Section: Introductionmentioning

confidence: 99%

“…As a coupled system, this variation of plate motion is also accompanied by a variation in flow structure. Spectra of the streamfunction field show that the flow field orients toward longer-wavelength structure as plate size increases, and the dominance of longer-wavelength structure enhances with plate speed (Mao 2021). So far, the focus has been on the influence of thermal blanket effect on plate motion and the overall flow structure.…”

Section: Introductionmentioning

confidence: 99%

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An insulating plate drifting over a thermally convecting fluid: the thermal blanket effect on plume motion and the emergence of a unidirectionally moving mode

Mao

2022

J. Fluid Mech.

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Floating rather stably above the convective mantle, continents exert a thermal blanket effect on the mantle by locally accumulating heat and altering the flow structure, which in turn affect continent motion. This thermal-mechanic feedback has been captured by a simplified model―a thermally insulating plate floating freely over a bottom-heated convecting fluid. Previous studies have revealed that, as plate size increases, plate motion transitions from long-term stagnancy over cold downwelling to short-term stagnancy over hot upwelling, termed stagnant modes (SMs) I and II, respectively, and eventually to a unidirectionally moving mode (UMM) with no stagnancy. During SM I/II, the adjacent hot/cold plumes are observed to move toward/away from the plate. The present study quantifies these plume motions through analysis on a partially insulated loop model established for SM I and SM II, respectively. The model predictions are well verified by results of numerical simulation. Moreover, the dominant frequency of plate speed is shown to increase linearly with plate size, with an abrupt jump as the coupling mode transitions from SM I to SM II. This suggests that the enhanced thermal blanket effect with plate size enables an increasingly fast feedback between the slowdown of a plate and the strengthening of hot upwelling which boosts plate motion. When plate motion is boosted before it stops, the UMM emerges. The predicted critical plate size for the UMM is well validated by simulation results. Geological implications of the results for continent motion, continent–mantle coupling and particularly the migration of plume and subduction sites are discussed.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

An insulating plate drifting over a thermally convecting fluid: the thermal blanket effect on plume motion and the emergence of a unidirectionally moving mode

Mao

2022

J. Fluid Mech.

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A random 2D walk of a submerged free-floating disc in a convective layer

Frick,

Popova,

Sukhanovskii

et al. 2023

Physica D: Nonlinear Phenomena

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Covering convection with a thermal blanket: numerical simulation and stochastic modelling

Huang

2024

J. Fluid Mech.

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Adding moving boundaries to convective fluids is known to result in non-trivial and surprising dynamics, leading to spectacular geoformations ranging from kilometre-scale karst terrains to planetary-scale plate tectonics. On the one hand, the moving solid alters the surrounding flow field, but on the other hand, the flow modifies the motion and shape of the solid. This leads to a two-way coupling that is significant in the study of fluid–structure interactions and in the understanding of geomorphologies. In this work, we investigate the coupling between a floating plate and the convective fluid below it. Through numerical experiments, we show that the motion of this plate is driven by the flow beneath. However, the flow structure is also modified by the presence of the plate, leading to the ‘thermal blanket’ effect where the trapped heat beneath the plate results in buoyant and upwelling flows that in turn push the plate away. By analysing this two-way coupling between moving boundary and fluid, we are able to capture the dynamical behaviours of this plate through a low-dimensional stochastic model. Geophysically, the thermal blanket effect is believed to drive the continental drift, therefore understanding this mechanism has significance beyond fluid dynamics.

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An insulating plate drifting over a thermally convecting fluid: the effect of plate size on plate motion, coupling modes and flow structure

Abstract: Abstract

Cited by 8 publications

References 46 publications

An insulating plate drifting over a thermally convecting fluid: the thermal blanket effect on plume motion and the emergence of a unidirectionally moving mode

An insulating plate drifting over a thermally convecting fluid: the thermal blanket effect on plume motion and the emergence of a unidirectionally moving mode

A random 2D walk of a submerged free-floating disc in a convective layer

Covering convection with a thermal blanket: numerical simulation and stochastic modelling

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