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- Arctic Ocean layering — Given the ubiquity of layering in environmental stratifications, an interesting example being double-diffusive staircase structures in the Arctic Ocean, we have obtained exciting new results from a joint theoretical and laboratory experimental study investigating the impact of multiple layering on internal wave propagation. Results for a simplified model demonstrate the nontrivial impact of multiple layering, and utilizing a weakly viscous, linear model that can handle arbitrary vertical stratifications, we have performed a direct comparison of theory with experiments. The model has been applied to a case study of a staircase stratification problem obtained from the Arctic Ocean, showing a rich landscape of transmission behavior. A detailed report of this study will be shortly published in the Journal of Fluid Mechanics. [read more "Arctic Ocean layering"]
- Lagrangian based methods for coherent structure detection — There has been a proliferation in the development of Lagrangian analytical methods for detecting coherent structures in fluid flow transport, yielding a variety of qualitatively different approaches. We have reviewed four approaches and demonstrated the utility of these methods via their application to the same sample analytic model, the canonical double-gyre flow, highlighting the pros and cons of each approach. Two of the methods, the geometric and probabilistic approaches, are well established and require velocity field data over the time interval of interest to identify particularly important material lines and surfaces, and influential regions, respectively. The other two approaches, implementing tools from cluster and braid theory, seek coherent structures based on limited trajectory data, attempting to partition the flow transport into distinct regions. All four of these approaches share the common trait that they are objective methods, meaning that their results do not depend on the frame of reference used. For each method, we also have considered a number of example applications ranging from blood flow and chemical reactions to ocean and atmospheric flows. A detailed report of this study has been published in Chaos. [read more "Lagrangian based methods for coherent structure detection"]
- The formation and fate of internal waves in the South China Sea — For over a decade, studies have targeted the South China Sea, where the oceans’ most powerful known internal waves are generated in the Luzon Strait and steepen dramatically as they propagate west. Confusion has persisted regarding their mechanism of generation, variability and energy budget, however, owing to the lack of in situ data from the Luzon Strait, where extreme flow conditions make measurements difficult. The ONR IWSIE team, of which we were fortunate to be part of, have used new observations and models to (1) show that the waves begin as sinusoidal disturbances rather than arising from sharp hydraulic phenomena, (2) reveal the existence of >200-metre-high breaking internal waves in the region of generation that give rise to turbulence levels >10,000 times that in the open ocean, (3) determine that the Kuroshio western boundary current noticeably refracts the internal wave field emanating from the Luzon Strait, and (4) demonstrate a factor-of-two agreement between modeled and observed energy fluxes, which allows us to produce an observationally supported energy budget of the region. Together, these findings give a cradle-to-grave picture of internal waves on a basin scale, which will support further improvements of their representation in numerical climate predictions. A detailed report of this study has been published in Nature. [read more "The formation and fate of internal waves in the South China Sea"]
- Graduate student and postdoc opportunities @ ENDLab — The group is looking for a new graduate student to study the field of Lagrangian transport structures and a new postdoc position for the study of near-inertial waves in the Arctic Ocean.
- New group member — Welcome to Dr. Ruth Musgrave, our new postdoc. Ruth has joined us from the Scripps Institution of Oceanography at UC San Diego. She will work on internal gravity waves in the Western Tropical Pacific.
- Arctic Ocean — After recently returning from the ArticMix cruise, we have received new ONR funding for field experiments in the Arctic Ocean using CPIES technology. Field studies will take place from 2017 to 2020 [read more].
- Ocean Hazards — We have received a new $3 million NSF Hazards-SEES grant to develop Lagrangian data analysis methods for the application to real world ocean hazards problems. This work will be a collaboration with WHOI, Virginia Tech., UC Berkeley, the US Coastguard and SINTEF, among others. The project will culminate with a field experiment off Martha’s Vineyard in summer 2018.
- Deep Sea Mining — We have just received MIT Environmental Solutions Initiative (ESI) seed funding to study the impacts of Deep Sea Mining, a very pressing issue for the global oceans.
- Headed to Palau — In summer 2016, we will be headed to Palau as part of the ONR FLEAT program, where will use PIES technology to make field measurements of the impacts of stratified flow encountering the abrupt topography of the Mariana Ridge system.
- Visit to India and South Korea — Dr. Sasan Ghaemsaidi, after defending his thesis in August, just returned from spending a month working with Prof. Jae Hun Park and Prof. Manikandan Mathur in Seoul, South Korea and Chennai, India, respectively.
- New group members — Welcome to Rohit Supekar and Boyu Fan, our group's new graduate students. Rohit has joined us from the Indian Institute of Technology Madras, Chenna. Boyu hails from Caltech and will work in a collaboration between Profs. Akylas and Peacock. [read more]
- New papers — We have several new publications just published or coming out in journals such as the Journal of Fluid Mechanics and Physics of Fluids. Check out our publications page for more details.