Grant: Research Tools and Instruments - Category 1 (<$150,000)

The vast majority of flows of environmental and engineering importance are turbulent. Many fluid engineering systems have rough surfaces, and the flow may be subjected to streamwise pressure gradients. Because of the complex nature of these flows, their structural characteristics are not well understood. The objective of this proposal is to obtain funds to acquire an image intensifier unit. The equipment will be used together with an existing high resolution particle image velocimetry (PIV) system to conduct cutting-edge research on a variety of complex near-wall turbulent flows. The research will conduct investigation of pressure gradient turbulent flows over rough surfaces, turbulent wall jets and shallow turbulent wakes over rough surfaces. The PIV data will be used to identify coherent or eddy structures within these flows, and to elucidate how these structures affects the transport of flow and mixing characteristics. The data will also enable the applicant to obtain accurate measurement of the mean velocities, Reynolds stresses, triple correlations and the budget terms in the transport equation for turbulent kinetic energy and Reynolds stresses. The proposed research will advance state of knowledge of complex turbulent flows of engineering importance. The physical understanding and high quality data sets will be valuable to the turbulence community in developing and validating more accurate turbulence models, to design more efficient effluent discharge systems, and to improve efficiency of fluid engineering systems. The research will also provide an opportunity to train high quality personnel. These will lead to dramatic and sustained improvements to society in terms of cost savings to manufacturers and safer environment through reduced vehicle emissions and enhanced dilution and mixing of wastewater in water bodies.