Professional Background:

My research focuses on problems of applied fluid dynamics which are environmentally and/or geophysically relevant. Presently, I am involved in 3 projects.

The first project's goal is to model the turbulent boundary layer generated by an unsteady pressure gradient, which can be found near the bottom of the ocean in relatively shallow water, as well inside the large blood vessel in our bodies. In the ocean, it is important to characterize the flow near the bottom as it mediates the exchange of matter (sediments, nutrients, pollutants, etc.) between the seabed and the rest of the water column. To achieve the goal, we solve the dynamic equations using many CPUs working together.

While the first project deals with phenomena which occur on a scale of a few centimeters very close to the bottom, the second project deals with large ad powerful waves that involve the entire water column. These waves are made possible by the difference in density between the water close to the surface (which is warmer) and the water close to the bottom, which is usually cooler. Just like surface gravity waves ride on the interface between two fluids of different density (water and air), these internal waves ride within the water column itself, at the interface between cool and warm water. On the surface, it is usually the wind that starts and feed energy into surface waves. Within the water column, the tide flowing over underwater obstacles can generate powerful waves, which can than propagate far from the generation region. Massachusetts Bay, just offshore of Boston, is a place where during the summer these waves can be observed every 12.4 hours, in sync with the tide. Using computer, we model how the waves are generate and eventually "crash" as the bottom shoal near the coast. The crashing process generates large currents near the bottom, with important consequences for the resuspension of sediments. Small marine organisms, like plankton can "surf" these waves to be carried inshore.

In the last project we actually move outside the ocean into the atmosphere. In certain areas of the world, such as the California coast, the atmosphere just above the ocean (a few thousand feet) or land is separated by a sharp interface from the upper portion, where the temperature suddenly increases and the humidity drops. The lower layer behaves as if it were a giant lake, bounded by mountains. The lower layer can sometimes "overspill" across gaps or over mountain, in which case it picks up speed as it moves downward. A region where this is thought to happen is the Sea of Japan east and south of Valdivostock, the major Russian port in the region. North of Vladivostock, a gap in the otherwise uninterrupted mountain range connects the ocean with an inland area where cold air accumulates during the winter. Under the appropriate circumstances this air flows across the gap and over the ocean. The combination of high winds and large temperature differences plays an important role in controlling how much heat is transferred from the ocean to the atmosphere, in turn affecting the distribution of water masses within the Sea of Japan.

I also teach a class called Fluid Dynamics for seniors and graduate students. Follow the links below if you want to learn more, and thank you for visiting my page!