|Seminar video on Youtube (See seminar)|
Monday, November 5th, 2018. Time: 12 noon
Place: O.C. Zienkiewicz Conference Room, C1 Building, UPC Campus Nord, Barcelona
A better understanding of sediment erosion and deposition processes is critical to the mission of the US Army Corps of Engineers and many other organizations concerned with flood protection, navigation, and riverine and coastal water resources. Long-term engineering of the Mississippi river, beach nourishment projects for coastal communities, and design of levees, breakwaters, and dunes for storm protection are just a few areas that turn on the interaction of fluids with granular materials. Hunter Rouse, "the father of modern hydraulics" wrote in 1939 that, "neither mathematical tools nor physical understanding of their use can be considered suciently far advanced to cope with so intricate a problem at the present time" . Today, the state of practice in computational modeling of sediment dynamics still relies heavily on empirical relationships.
In recent decades, however, much progress has been made on the development of numerical methods capable of obtaining accurate solutions of fluid-grain dynamics at the microscale as well as on rigorous methods for obtaining practical computational models at larger scales. Perhaps soon mathematical tools and physical understanding will be suciently advanced to cope with the intricate problem of sediment dynamics. This presentation will describe approaches for both grain-resolving and volume-averaged models. For grain-resolving simulations we present a combination of level set [1,2] and immersed/embedded boundary methods [4,5] for simulating microscale air-water-solid dynamics using nite element methods for incompressible flow of the fluid phases and discrete element methods for the dynamics of the solid grains. For volume-averaged approaches we consider and extension of recent doubly-averaged formulations based on mass and momentum conservation for two fluid and one granular phase, which also uses some of the same nite element and level set tools.
 S. Osher and J. A. Sethian. Fronts propagating with curvature-dependent speed: Algorithms based on Hamilton-Jacobi formulations. Journal of Computational Physics, 79:1249, (1988).
 C.E. Kees, I. Akkerman, M.W. Farthing, and Y. Bazilevs. A conservative level set method suitable for variable-order approximations and unstructured meshes. Journal of Computational Physics, 230(12):4536-4558 (2011).
 H. Rouse. An analysis of sediment transportation in the light of uid turbulence. United States Department of Agriculture, (1939).
 C.S. Peskin. The immersed boundary method. Acta Numerica, 11:479-517 (2002).
 A. Main and G. Scovazzi. The shifted boundary method for embedded domain computations. Part II: Linear advectiondiffusion and incompressible NavierStokes equations. Journal of Computational Physics, 372: 996-1026 (2018).
Chris Kees, Ph.D. at Coastal and Hydraulics Laboratory US Army Engineer Research & Development Center