Coastal Engineering Faculty Candidate Seminar

Date: April 17 (Thursday), 2014 Time: 2:00 – 3:00 pm. Kaufman Hall Room 239   Nonlinear Wave Dynamics from Fluidized Cohesive Sediments in Abyssal Ocean Navid Tahvildari, Ph.D. , Environmental Fluid Mechanics Laboratory, Stanford University   Abstract Coastal environment is affected by nonlinear wave processes over ocean surface and in its interior. Free-surface wave spectrum is strongly modulated in shallow water due to nonlinear interactions among harmonics and their coupling with currents and sediment bed. Therefore, to have an accurate assessment of wave impact on coastline, it is necessary to account for the dissipative effect of cohesive sediments as modified by nonlinear interactions in surface wave spectrum. On the other hand, surface waves can induce waves over water/fluid-mud interface which can break and result in turbidity in water column. Interfacial-wave induced mixing can affect the exchange of nutrients (or pollutants) with the seabed. These waves are in fact ripple-size internal waves (waves in ocean interior) that are generated due to surface-interface nonlinear resonant interactions. In deeper waters, oceanic internal waves are generated due to propagation of surface tides over prominent topographic features such as submerged ridges and continental shelf breaks. These large-amplitude and thus nonlinear waves transport sediment and nutrient-rich water to inner continental shelf. Therefore, their energetics at the generation site and the accompanied mixing is significant for coastal morphology and habitat. In this presentation, the aforementioned subjects are examined via theoretical methods and numerical simulations. Future research directions are also presented. Short Bio Dr. Navid Tahvildari received his M.Sc. in Civil Engineering from Sharif University of Technology in 2007 and Ph.D. in Coastal & Ocean Engineering at Texas A & M University in 2011. Now he’s a Post.Doc. in Environmental Fluid Mechanics Laboratory at Stanford University. His research interests are focused on nonlinear wave-wave interactions, wave-sediment interactions, interfacial and internal waves as well as mixing and turbulence in stratified flow.

Posted By: Gary Schafran
Date: Wed Apr 16 06:49:26 EDT 2014