Physics
Shape and dynamics of seepage erosion in a horizontal granular bed
Document Type
Article
Abstract
We investigate erosion patterns observed in a horizontal granular bed resulting from seepage of water motivated by observation of beach rills and channel growth in larger scale land forms. Our experimental apparatus consists of a wide rectangular box filled with glass beads with a narrow opening in one of the side walls from which eroded grains can exit. Quantitative data on the shape of the pattern and erosion dynamics are obtained with a laser-aided topography technique. We show that the spatial distribution of the source of groundwater can significantly impact the shape of observed patterns. An elongated channel is observed to grow upstream when groundwater is injected at a boundary adjacent to a reservoir held at constant height. An amphitheater (semicircular) shape is observed when uniform rainfall infiltrates the granular bed to maintain a water table. Bifurcations are observed as the channels grow in response to the groundwater. We further find that the channels grow by discrete avalanches as the height of the granular bed is increased above the capillary rise, causing the deeper channels to have rougher fronts. The spatiotemporal distribution of avalanches increase with bed height when partial saturation of the bed leads to cohesion between grains. However, the overall shape of the channels is observed to remain unaffected indicating that seepage erosion is robust to perturbation of the erosion front. © 2012 American Physical Society.
Publication Title
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics
Publication Date
10-10-2012
Volume
86
Issue
4
ISSN
1539-3755
DOI
10.1103/PhysRevE.86.041304
Repository Citation
Berhanu, Michael; Petroff, Alexander; Devauchelle, Olivier; Kudrolli, Arshad; and Rothman, Daniel H., "Shape and dynamics of seepage erosion in a horizontal granular bed" (2012). Physics. 111.
https://commons.clarku.edu/faculty_physics/111
