UC Berkeley

Turbulence is an important and ubiquitous phenomena in fluid mechanics that underpins many natural processes. For environmental engineers, turbulence is especially critical to understanding the fate and transport of contaminants in nature. Reliable calculations by transport models of the spread of substances introduced into the atmosphere or into the water supply requires that the physics of turbulent motions be captured with high fidelity. Whereas analytical and numerical approaches to describing turbulence can often be intractable and computationally prohibitive, quantitative imaging methods can provide valuable insights into both the phenomenology of turbulence and the interactions with its surroundings. This dissertation describes a series of research projects based on experimental observations of turbulent motions and their affect on natural processes. First, the development of a field-ready, quantitative-imaging tool capable of capturing the complex, three-dimensional turbulent motions most responsible for turbulent mixing is described. Second, a study on the dynamics of momentum transfer across the air-water interface within a vegetated wetland using the newly developed tool is described. Lastly, an experiment using high-speed cinematography to examine the kinematic response of hummingbirds navigating a complex, turbulent flow is described.