2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 218-4
Presentation Time: 9:00 AM-6:30 PM


MYRE, Joseph, Department of Geosciences, University of Arkansas, 216 Ozark Hall, University of Arkansas, Fayetteville, AR 72701 and COVINGTON, Matthew D., Department of Geosciences, University of Arkansas, 216 Ozark Hall, Fayetteville, AR 72701, joemyre@gmail.com

The understanding of the processes that generate soluble bedforms is incomplete. In particular, the morphogenesis of scallops presents a puzzle for the current theory of limestone dissolution. Current theory predicts that limestone dissolution rates should not vary within scallops under turbulent flow conditions, at least on the scales of scallops found in nature.

Previous studies using computational fluid dynamics (CFD) to examine the processes driving the morphogenesis of scallops have made simplifying assumptions to ensure a tractability. Consequently, fine scale effects associated with the driving processes are not modeled. Using a lattice-Boltzmann method for CFD and large-eddy simulation (LES) we are able to relax previous simplifying assumptions to model additional effects of the physico-chemical driving processes.

This toolset provides the means to incorporate sub-grid scale turbulent effects into the flow dynamics. As a partial means for resolving the conundrum surrounding scallops, these additional effects reveal turbulent structures that can enhance solute transport away from the fluid-solid interface, giving rise to a spatially variable and increased dissolution rate. To examine non-idealized scallops for the first time, we use low-cost 3-dimensional scanning technology to record natural scallops and incorporate the 3D scans as simulation geometries. We then simulate the physico-chemical processes occurring in a real-world system.