Fluid resonance in elastic-walled englacial transport networks

Englacial water transport is an integral part of the glacial hydrologic system, yet the geometry of englacial structures remains largely unknown. In this study, we explore the excitation of fluid resonance by small amplitude waves as a probe of englacial geometry. We model a hydraulic network consis...

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Bibliographic Details
Published inJournal of glaciology Vol. 67; no. 266; pp. 999 - 1012
Main Authors McQuillan, Maria, Karlstrom, Leif
Format Journal Article
LanguageEnglish
Published Cambridge, UK Cambridge University Press 01.12.2021
Subjects
Boundary conditions
Crack geometry
Cracks
Damping
Excitation
Geometry
Glaciation
Glacier geophysics
glacier hydrology
Glaciers
glaciological model experiments
Gravity
Hydrology
Ice cover
Ice sheets
Ice thickness
Investigations
Mountain glaciers
Oscillatory waves
Resonance
Resonant frequencies
Transport
Velocity
Viscosity
Water transport
Wave motion
Waves
glaciological model experiments
glacier hydrology
Glacier geophysics
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Summary:Englacial water transport is an integral part of the glacial hydrologic system, yet the geometry of englacial structures remains largely unknown. In this study, we explore the excitation of fluid resonance by small amplitude waves as a probe of englacial geometry. We model a hydraulic network consisting of one or more tabular cracks that intersect a cylindrical conduit, subject to oscillatory wave motion initiated at the water surface. Resulting resonant frequencies and quality factors are diagnostic of fluid properties and geometry of the englacial system. For a single crack–conduit system, the fundamental mode involves gravity-driven fluid sloshing between the conduit and the crack, at frequencies between 0.02 and 10 Hz for typical glacial parameters. Higher frequency modes include dispersive Krauklis waves generated within the crack and tube waves in the conduit. But we find that crack lengths are often well constrained by fundamental mode frequency and damping rate alone for settings that include alpine glaciers and ice sheets. Branching crack geometry and dip, ice thickness and source excitation function help define limits of crack detectability for this mode. In general, we suggest that identification of eigenmodes associated with wave motion in time series data may provide a pathway toward inferring englacial hydrologic structures.
ISSN:0022-1430
1727-5652
DOI:10.1017/jog.2021.48