Preprints
Filtering by Subject: Fluid Dynamics
Three-dimensional mineral dendrites reveal a non-classical crystallization pathway
Published: 2024-03-03
Subjects: Earth Sciences, Fluid Dynamics, Geochemistry, Mineral Physics, Physical Sciences and Mathematics, Physics
Manganese (Mn) dendrites are a common type of mineral dendrite that typically forms two-dimensional structures on rock surfaces. Three-dimensional (3D) Mn dendrites in rocks have rarely been reported, hence their growth implications have largely escaped attention. Here, we combine high-resolution X-ray and electron-based data with numerical modelling to give the first detailed description of [...]
Deep Learning Improves Global Satellite Observations of Ocean Eddy Dynamics
Published: 2024-01-15
Subjects: Artificial Intelligence and Robotics, Fluid Dynamics, Oceanography and Atmospheric Sciences and Meteorology
Ocean eddies help shape marine ecosystems, large-scale ocean circulation, and global climate through their non-linear interactions. Observing eddies poses a major challenge due to their chaotic evolution across a wide range of spatio-temporal scales. Satellite-derived estimates of surface ocean currents significantly distort and smooth eddies and, consequently, strongly underestimate the strength [...]
Power-law premelting in wire regelation
Published: 2024-01-13
Subjects: Fluid Dynamics, Glaciology, Other Physics
Wire regelation is a common tabletop demonstration of the pressure-dependence of the ice melting temperature in which a loaded wire moves from top to bottom through a block of ice, yet leaves the block intact. With the background temperature fixed at the bulk melting point $\sim0\,^{\circ}$C, the elevated ice and liquid pressures beneath the wire cause melting because of the negative Clapeyron [...]
Two-dimensional ideal magnetohydrodynamic waves on a rotating sphere under a non-Malkus field: I. Continuous spectrum and its ray-theoretical interpretation
Published: 2023-10-05
Subjects: Fluid Dynamics
Two-dimensional (2D) ideal incompressible magnetohydrodynamic (MHD) linear waves at the surface of a rotating sphere are studied as a model imitating the outermost Earth's core or the solar tachocline. This thin conducting layer is permeated by a toroidal magnetic field whose magnitude depends only on the latitude. The Malkus background field, which is proportional to the sine of the colatitude, [...]
Complementary classifications of aeolian dunes based on morphology, dynamics, and fluid mechanics
Published: 2023-10-03
Subjects: Earth Sciences, Fluid Dynamics, Geomorphology, Other Earth Sciences, Physical Sciences and Mathematics, Physics, Planetary Geomorphology, Planetary Sciences, Sedimentology
Dunes form where winds blow over a bed of mobile sediment grains – conditions that are common in our solar system. On Earth, dunes abound in arid continental interiors and along sandy coastlines. Dune fields have also been recognized on other planetary bodies, including Venus, Mars, Saturn’s moon Titan, and Pluto. Despite the relatively basic conditions required for their formation, dunes adopt a [...]
Linear analysis of ice-shelf topography response to basal melting and freezing
Published: 2023-04-28
Subjects: Applied Mathematics, Dynamic Systems, Earth Sciences, Fluid Dynamics, Glaciology, Physical Sciences and Mathematics, Physics
Floating ice shelves in Antarctica and Greenland limit land-ice contributions to sea level rise by resisting the flow of grounded ice. Melting at the surface and base of ice shelves can lead to destabilisation by promoting thinning and fracturing. Basal melting often results in channelised features that manifest as surface topography due to buoyancy. The assumption of hydrostatic flotation [...]
Dampening effect of global flows on Rayleigh-Taylor instabilities: Implications for deep-mantle plumes vis-à-vis hotspot distributions
Published: 2023-01-18
Subjects: Earth Sciences, Fluid Dynamics, Numerical Analysis and Computation
It is a well-accepted hypothesis that deep-mantle primary plumes originate from a buoyant source layer at the core-mantle boundary (CMB), where Rayleigh–Taylor (RT) instabilities play a key role in the plume initiation process. Previous studies have characterized their growth rates mainly in terms of the density, viscosity and layer-thickness ratios between the denser overburden and the source [...]
A breakthrough in fast flood simulation
Published: 2022-12-05
Subjects: Fluid Dynamics, Hydrology
The current status of technological advancement does not allow to generate complete flood simulations in real-time for large geographic areas. This hinders warning-systems, interactive planning tools and detailed forecasts and as a consequence the population cannot be quickly or reliably informed of where large masses of water will flow. Our novel method computes flood hazard maps over three [...]
Efficiently Simulating Lagrangian Particles in Large-Scale Ocean Flows – Data Structures and their Impact on Geophysical Applications
Published: 2022-10-26
Subjects: Fluid Dynamics, Numerical Analysis and Scientific Computing, Oceanography
Studying oceanography by using Lagrangian simulations has been adopted for a range of scenarios, such as the determining the fate of microplastics in the ocean, simulating the origin locations of microplankton used for palaeoceanographic reconstructions, for studying the impact of fish aggregation devices on the migration behaviour of tuna. These simulations are complex and represent a [...]
GANSim-surrogate: An integrated framework for conditional geomodelling and uncertainty analysis
Published: 2022-10-24
Subjects: Computational Engineering, Earth Sciences, Environmental Engineering, Fluid Dynamics, Geology, Geophysics and Seismology, Hydrology, Sedimentology
We propose a deep-learning framework (GANSim-surrogate) for conditioning subsurface geomodel realizations to static data and dynamic flow data. The static data includes well facies data, interpreted facies probability maps, and non-spatial global features, while dynamic data can include well data such as pressures and flow rates. The framework consists of a Convolutional Neural Network (CNN) [...]
A genetic model of the magnetite-apatite deposits on El Laco volcano by extrusion of iron-rich melt
Published: 2022-08-25
Subjects: Dynamical Systems, Earth Sciences, Fluid Dynamics, Geochemistry, Geology, Numerical Analysis and Scientific Computing, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Magnetite-apatite deposits are important sources of iron and other metals. A prominent exam- ple are the magnetite lavas at the El Laco volcano, Northern Chile. Their formation processes remain debated. Here, we test the genetic hypothesis that an Fe-rich melt separated from silicate magma and ascended along collapse-related fractures. We complement recent analy- ses with thermodynamic modelling [...]
A Simple Framework for Calibrating Hydraulic Flood Inundation Models using Crowd-sourced Water Levels
Published: 2022-08-23
Subjects: Civil Engineering, Fluid Dynamics, Hydraulic Engineering, Hydrology, Water Resource Management
Floods are the most commonly occurring natural disaster, with the Centre for Research on the Epidemiology of Disasters 2021 report on “The Non-COVID Year in Disasters” estimating economic losses worth over USD 51 million and over 6000 fatalities in 2020. The hydrodynamic models which are used for flood forecasting need to be evaluated and constrained using observations of water depth and extent. [...]
Ascent rates of 3D fractures driven by a finite batch of buoyant fluid
Published: 2022-06-20
Subjects: Fluid Dynamics, Geology, Glaciology, Mechanics of Materials, Volcanology
Propagation of fluid-filled fractures by fluid buoyancy is important in a variety of settings, from magmatic dykes and veins to water-filled crevasses in glaciers. Industrial hydro-fracturing utilises fluid-driven fractures to increase the permeability of rock formations, but few studies have quantified the effect of buoyancy on fracture pathways in this context. Analytical approximations for the [...]
Tidal Turbine Array Modelling using Goal-Oriented Mesh Adaptation
Published: 2022-04-29
Subjects: Civil and Environmental Engineering, Fluid Dynamics, Geophysics and Seismology, Numerical Analysis and Computation, Partial Differential Equations
Purpose: To examine the accuracy and sensitivity of tidal array performance assessment by numerical techniques applying goal-oriented mesh adaptation. Methods: The goal-oriented framework is designed to give rise to adaptive meshes upon which a given diagnostic quantity of interest (QoI) can be accurately captured, whilst maintaining a low overall computational cost. We seek to improve the [...]
Diapycnal Displacement, Diffusion, and Distortion of Tracers in the Ocean
Published: 2022-01-07
Subjects: Applied Mathematics, Fluid Dynamics, Non-linear Dynamics, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Small-scale mixing drives the diabatic upwelling that closes the abyssal ocean overturning circulation. Indirect microstructure measurements of in situ turbulence suggest that mixing is bottom enhanced over rough topography, implying downwelling in the interior and stronger upwelling in a sloping bottom boundary layer. Tracer release experiments (TREs), in which inert tracers are purposefully [...]