The Effect of Sand Fraction and Event Evolution on Wave-Supported Mud Flows

U. Delaware Investigators: T.-J. Hsu, Liangyi Yue, Yashar Rafati.

U. Washington Investigator: Alex Horner-Devine (UW), Andrea Ogston (UW).

Collaborators: Andrew Manning (HR Wallingford; Univ. Hull)

Project summary:

The major goal of this study is to understand how the sand fraction and evolution of transport events can dictate the initiation, transport and termination of wave-supported gravity currents (WSGC) and builds depositional signatures. We hypothesize that the particle size distribution in natural sediment, especially the sand fraction, can alter flow and sediment dynamics during the initiation, transport, and termination of WSGC due to the formation of ripples, armoring, and changes in turbulent modulation, leading to distinct signatures in the depositional record that may reveal the history of transport and deposition.

We use high-resolution laboratory and numerical model experiments to develop a mechanistic understanding of the role of sand fraction in transport and deposition and compare the processes that this investigation reveals with the bottom boundary layer and seabed data collected previously from the Waipaoa and Eel River margins in order to provide a better-informed basis for the interpretation of transport processes and deposition in other coastal systems.

Products:

Yue, L., Cheng, Z., & Hsu, T.-J. (2020). A turbulence-resolving numerical investigation of wave-supported gravity flows. Journal of Geophysical Research: Oceans, 125, e2019JC015220.

The source code and the case setup to reproduce the same results are publicly available via the repository maintained by GitHub:

https://github.com/yueliangyi/TURBID

https://github.com/yueliangyi/TURBID/tree/master/spike/wave_supported_gravity_flow

Cheng, Z., Chauchat, J., Hsu, T.-J., Calantoni, J. (2018) Eddy interaction model for turbulent suspension in Reynolds averaged Euler-Lagrange simulation of steady sheet flow, Advances in Water Resources, 111, 435-451.

Cheng, Z., Hsu, T.-J., Calantoni, J. (2017) SedFoam: A multi-dimensional Eulerian two-phase model for sediment transport and its application to momentary bed failure, Coastal Engineering, 119, 32-50.

The numerical model used in Cheng et al. (2015) has been made available to the public as an open-source model via Community Surface Dynamics Modeling System (CSDMS) model repository maintained by Github:

https://github.com/csdms-contrib/finesed3d

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