Research Abstracts Online
January 2009 - March 2010
University of Minnesota Twin Cities
Institute of Technology
Department of Civil Engineering
PI: John S. Gulliver
Two-phase Transport in Turbulent Environmental Flow
These researchers are involved in two projects investigating turbulent flow. The first concerns the excess water discharged from hydraulic structures such as dams as reservoirs. The water is usually discharged as a high velocity jet into a relatively stagnant pool that creates a turbulent mixing and recirculation zone. The resulting bubbles affect gas concentrations in the water, which in turn can affect fish in the pool with a disease similar to the bends. The main goal of this project is to evaluate the performance of existing turbulent models (RANS model and LES model) in simulating bubble-water mass transfer.
The second project concerns hydrodynamic separators, which are prefabricated, small-scale, underground structures designed to remove particulate pollutants from storm-water runoff and improve water quality. The effectiveness of hydrodynamic separators has historically been evaluated with monitoring, but the results of these evaluations vary substantially and do not provide adequate predictive models for these devices. A methodology has recently been developed for controlled testing that produces more accurate results as compared to monitoring. These researchers use two- and three-dimensional modeling software with CFD to simulate fluid dynamics and sedimentation for several hydrodynamic separators. Calibrated numerical models will be used to estimate sedimentation in similar devices with different configurations, test potential design improvements, estimate frequency of routine maintenance due to sediment accumulation, evaluate existing design and sizing criteria, and estimate long-term sediment accumulation.
X.J. Cheng, Visiting Faculty Collaborator, Sun Yat Sen University, China
Andy Erickson, Research Associate
Md Shafayat Jamil, Graduate Student