Abstract : Fluid-structure interactions appear on many different scales of our planet. For example, centimeter-scale pebble stones are shaped by flow erosion, while kilometer-scale karst terrains are a result of dissolution. Even the planetary-scale plate tectonics are believed to be driven by the convection in Earth’s mantle. In this minisymposium, we focus on lab-scale experiments and math modeling of such geophysical fluid-structure interactions, exploring the connections between processes like convection, erosion, dissolution, and melting. With a diverse group of speakers, this minisymposium will initiate a new and combined effort to address these important geophysical phenomena.
[04348] How Fluid-Mechanical Erosion Creates Anisotropic Porous Media
Format : Talk at Waseda University
Author(s) :
Bryan Quaife (Florida State University)
Nick Moore (Colgate University)
Jake Cherry (Florida State University)
Shang-Huan Chiu (Lehigh University)
Abstract : When a porous medium erodes, microscopic changes of the grain morphology give rise to larger-scale features such as channelization. Using a boundary integral formulation, we characterize these changes by simulating erosion of porous media. A Cauchy-integral formulation and associated quadrature formulas enable us to resolve dense configurations of nearly contacting bodies. We observe that substantial anisotropy develops over the course of erosion; that is, the configurations that result from erosion permit flow in the longitudinal direction more easily than in the transverse direction by up to a factor of six. These results suggest that the erosion of solid material from groundwater flows may contribute to previously observed anisotropy of natural porous media.
[04569] Moving boundaries in thermal convection
Format : Talk at Waseda University
Author(s) :
Jun Zhang (New York University)
Abstract : With simple experiments, we study how mobile boundaries interact with thermally convective flows. When turbulence intensity in thermal convection is sufficiently large, flow patterns are random. However, if a mobile boundary is added to the system, and allowed to freely interact with the surrounding flows, the structure-fluid system may show orderly behaviors, and the flow patterns also become more regular. Geophysical motivations and potential applications will also be discussed in this talk.
[04835] Using asymptotic analysis to improve numerical methods for multiphase flows
Format : Talk at Waseda University
Author(s) :
Eric William Hester (UCLA)
Andrea Bertozzi (UCLA)
Abstract : Diffuse-interface methods approximate discontinuous boundary conditions with smooth source terms - avoiding the need to explicitly discretise multiphase interfaces. But this approximation only converges in the limit. Using the signed-distance function I will outline a general framework for the asymptotic analysis of diffuse-interface methods. I will thereby optimise diffuse-interface simulations of fluid-structure interaction, melting and dissolving ocean icebergs, and dynamic contact lines in three-phase fluids.
[04665] Laser shot on water and ice
Format : Online Talk on Zoom
Author(s) :
Daosheng Deng (Fudan University)
Abstract : The strong interaction between laser and ice or water, arising from the strong photothermal effect, can lead the diverse intriguing phenomena. This talk will present the dancing bubble generated in water by laser, and report the melting of ice under the laser illumination.
[04383] A simple model on what drives continental drifts
Format : Talk at Waseda University
Author(s) :
Jinzi Mac Huang (New York University Shanghai)
Abstract : It is well known that the continents of earth do not stay in place, and thermal convection in Earth’s mantle is believed to be the driving force of these motions. How does mantle convection couple to the continental drift? Does the moving continent affect the mantle motion beneath it? We address these questions through a simple fluid-structure interaction model, exploring the fluid mechanical origin of continental drift and the possibility of modeling tectonic plate interactions.
[05512] Computing the diffusivity of a particle subject to dry friction with colored noise
Format : Talk at Waseda University
Author(s) :
Laurent Mertz (City University of Hong Kong)
Josselin Garnier (Polytechnique)
Abstract : Experimental studies and numerical simulations have been devoted to the motion of an object subjected to a dry friction and an external random force. The experimental and numerical observations suggest that the variance of the object displacement grows linearly with time. Here, the variance growth rate is called diffusivity. The goal of this paper is to propose efficient stochastic simulation methods for computing the diffusivity when the external random force is white or colored noise.
[04815] The Formation of Karst Pinnacles
Format : Online Talk on Zoom
Author(s) :
Nick Moore (Colgate University)
Abstract : Recent experiments demonstrate how dissolution, in conjunction with gravitationally-induced convective flows, can create sharp geometric features. These laboratory-created structures give insight into geological features known as karst pinnacles. A new computational approach reveals convergence to a morphological attractor with high, yet finite, tip curvature. These results reverse previous hypotheses on shock formation (i.e. finite-time blowup of tip curvature), agree well with laboratory experiments, and enable simple estimates for the age of geological structures.
