Research
Our research focus on a wide range of applications of environmental fluid dynamics. We use both observations and modeling to understand turbulence, particle-fluid interactions, and transport phenomena. Our primary research subjects are within water resources, including natural water bodies and engineered water systems. We also collaborate with scientists and physicians to study broader fluid problems.
Current research topics:
Natural seeps of hydrocarbon bubbles from shallow to deep seas
Developing new instrument to better understand marine seeps
Underwater gas blowout in high-speed releases
Turbulence structures in the Missouri River and their influences on transport of fish eggs and larvae
Sediment impacts on freshwater mussels
Understanding mechanisms of environmental transmission of avian flu
Wind-driven seed dispersal and the effect of the seed morphology
Funded by the National Science Foundation (NSF), we conducted field observations of natural seeps at Green Canyon (GC) 185, collected rich data using our newly developed RPiPIV system, along with measurements of gas flux and acoustic backsatter from bubbles using several single-beam and multi-beam echo-sounders mounted on the research vessel and two underwater robots (AUV Sentry and ROV Jason).
Funded by the USGS Aquatic Invasive Species program, we are investigating the effect of turbulence on the egg drift in a unique reach of Missouri River, where a series of channel-training structures and bedforms are present (see upper left figure). We are collaborating with USGS scientists on using observations and modeling to quantify the fine-scale turbulent structures and their influence on the dispersion of egg particles in water.
We studied the flight dynamics of a bent-awn plumegrass called Saccharum contortum. We applied both laboratory experiments and numerical simulations. The goal of this study is to determine how the tiny hairs can affect the seed drag in various wind conditions. From experiment, we found that the Saccharum contortum seeds have a terminal free fall velocity primarily in the range of 1–2 m/s. The seed lacking hairs exhibited a significantly higher terminal velocity, reaching 2.34 times the average velocity observed in seeds with hairs. For seeds with hairs, terminal velocity exhibited a linear relationship with seed mass, while the drag coefficient displayed a power-law dependence on the Reynolds number. The CFD simulation demonstrates that the body of Saccharum contortum seeds possesses a streamlined shape, with frictional forces within the boundary layer dominating drag during free fall and upward wind conditions. The presence of hairs leads to an increase in pressure drag, suggesting the formation and influence of eddy motions in the wake of seeds. See our publication here.