Turbulent Flows occur in many natural and engineering systems, e.g., high-speed marine vessels moving through water, erosion at the river bed, pollution spreading in the urban area, and so on. The turbulence is the main reason of high friction drag and noise generation. We perform high-resolution velocity measurements within the turbulent boundary layers to understand the mechanics of turbulent flows. We also develop drag reduction technologies such as the bio-inspired super-hydrophobic surfaces. [Read More]

The Super-Hydrophobic Surfaces (SHSs) have received growing attentions due to their potentials for self-cleaning, anti-corrosion, anti-biofouling, friction reduction, and etc. Their performances are attributed to the presence of gas bubbles in the micro-cavities. However, these entrapped gas bubbles are subjected to instabilities induced by pressures, flows, and gas diffusions. We use optical imaging to study the interfacial dynamics at the submersed SHSs. [Read More]

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]