Formation and Evolution of Sediment Waves: Integration of Quantitative Modeling and Field Observations

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The proposed research will extend a recently developed framework for analyzing flow/sediment bed interactions to bottom currents, debris flows and tsunamis. Differences with regard to wave orientation relative to flow direction and slope, up and downstream symmetry, direction of migration etc. will be compared in detail to corresponding field observations, in order to draw conclusions about the genesis of specific sediment wave fields. The framework for conducting both linear stability analysis and nonlinear simulations is based on the full three-dimensional Navier-Stokes equations, rather than the depth-averaged shallow water equations most commonly employed to date. A new Ph.D. post-doc will do most of the work in collaboration with the PI. The PI hopes that the proposed research will elevate the description of sediment wave formation from largely qualitative arguments to advanced, quantitative models on which we can base rigorous linear stability analyses as well as fully nonlinear simulations. In this way, it will enable us to distinguish between sediment waves generated by turbidity and bottom currents, debris flows and tsunamis, so that different sediment wave fields can be classified according to their mechanism of generation.Broader impact: Stated broader impacts include support of quantitative, engineering-based modeling approaches within the earth science community. The work has relevance to the mission of the NSF-sponsored Community Surface Dynamics Modeling System (CSDMS). The project will also support a graduate student, as well as undergraduates and outreach to high school students.