Research
Drag Reduction and Flow Control by Super-Hydrophobic Coatings
The hydrodynamic skin-friction in turbulent flows contributes to 60-70% of the total drag of most surface and subsurface vessels. Reducing the friction drag could lead to improvement of speed, range and maneuverability, as well as a reduction of fuel consumption and CO2 emission. Recently, superhydrophobic surface (SHS), inspired from the lotus leaf, has been shown to achieve a substantial drag reduction, as high as 90%. The SHS traps a thin gas layer between the solid surface and flowing liquid, and thereby an effective slip boundary. However, implementing SHS in real large-scale engineering systems, such as ships, is still highly challenging for issues, such as non-uniform surface roughness, unstable gas layer, and gas dissolution. Our lab aims to address these issues by performing research at the following areas:
– Diffusive and convective gas transfer from SHS to surrounding liquid.
– Stability of gas layer on SHS in turbulent flows.
– Flow structure and Turbulence on large SHS in fully developed flows.
Collective Behavior is cornerstone of many biological systems, from the cell colonies, insect swarms, bird flocks, to human crowds. Living in groups can provide numerous benefits, including predator avoidance, resource exploitation, and energy savings. We use a combination of experimental observations and mathematical modelings to uncover the mechanism of collective behavior. By learning the natural systems, we aim to design efficient multi-robotic systems. [Read More]
Development of Optical Imaging Technologies: In our lab, we develop a variety of optical imaging and tracking technologies for applications in fluid mechanics, animal ecology, and environmental and life sciences. Most of them are three-dimensional, examples include: (i) flow velocity field measurements using digital holographic microscopy and PIV; (ii) flocking bird tracking using multi-camera stereo-imaging; (iii) interfacial and droplet visualizations using laser induced fluorescence. [Read More]
