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Click on a title or picture for more details. For an update on each of the following project, check our publication list. free boundaries in thermal convection: simulating continental drift At high Rayleigh numbers, thermal turbulence often organizes itself to form a large-scale circulation. Such flow structures can be induced and modified by local thermal disturbances. In this experiment, we introduce a freely-moving upper boundary in Bérnard convection to study the coupling between the motions of a single upper boundary and a thermal convective fluid. We found that the boundary (a model continent) can be driven to execute a periodic motion. This result is consistent with the observation that the Atlantic Ocean has closed and then re-opened several times in the past 2.5 billion years. For more details click on the picture. spontaneous thrust generation and forward flight from harmonic flapping In collaboration with Nicolas Vandenberghe and Steve Childress. We study how simple flapping motion of a rigid, symmetric wing generates thrust as a result of spontaneous symmetry breaking. We further examine the relationship between the flapping frequency, amplitude and forward flight speed. For detail, click on the picture. flag flapping in laminar flows: the dynamics of passive swimmers A flapping filament in a quasi-two-dimensional soap film flow tunnel: the resulting motion is similar to a flapping flag. We study the dynamics of a single filament as well as multiple interacting filaments under the action of an incoming laminar flow. Several stable, dynamical states are observed in this system. We also compare these passive dynamics with actively swimming bodies: such as fish. For more details click on the picture. to reduce the drag, be flexible (flexible bodies yields lower drag in flows) In collaboration with Silas Alben and Michael Shelley. Through a prototype experiment, we study how flexible objects streamline themselves and experience less drag (compared with rigid bodies) under strong fluid forces. In Nature, tree branches, broad leaves survive gusty winds possibly because they are flexible. Click on the picture for more details. the first realization of tubeless siphons using flowing soap films In collaboration with Julien Psaute and Jonathan Kamler. We sometimes need to use a siphon (a hose) to empty a gasoline tank. The siphon will not work if the hose has an opening somewhere in the middle. In our lab, we just created a siphon that is totally exposed to the atmosphere. a friction-driven oscillator Solid-on-solid friction is studied in a friction driven oscillator. We observe a stochastic process where sticking (rolling) alternates with slipping. The system is driven externally to a self-organized state that is not critical. For more details click on the picture. 3-D visualization of thermal turbulence We are studying a technique for visualizing thermal convection. Traditional shadowgraphs collapse the three dimensional information in a convection cell onto a two dimensional plane. We use the principles of stereo vision to recover the 3D structure using two sets of shadowgraphs taken from slightly different angles. For more details click on the picture. a valveless pump that tansfers fluid A valveless pump is constructed after the suggestion of Dr. Peskin and Dr. Jung. It is a impedance induced flow system in a closed circle. A directional flow can be realized when a periodic forcing is applied. The direction of flow depends upon the frequency and amplitude. The detailed mechanism is still a mystery. For more details click on the picture.