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Full-Text Articles in Engineering

Refining Greenstep: Impacts Of Vehicle Technologies And Its/Operational Improvements On Travel Speed And Fuel Consumption Curves, Kelly Clifton, Alexander Y. Bigazzi Nov 2011

Refining Greenstep: Impacts Of Vehicle Technologies And Its/Operational Improvements On Travel Speed And Fuel Consumption Curves, Kelly Clifton, Alexander Y. Bigazzi

Civil and Environmental Engineering Faculty Publications and Presentations

This report describes analysis undertaken to establish a method for incorporating traffic operations and ITS strategies into the GreenSTEP model. We first discuss operations impacts on fuel economy and delay from the literature. Then, an investigation of delay adjustments in GreenSTEP shows that different methods of representing delay changes lead to similar (and small) impacts on fuel economy. From this result we establish average speed adjustment by congestion level as the preferred method for incorporating delay effects from operations improvements. An investigation of aggregate traffic operations impacts produces estimates of base speeds without operations improvements, maximum speeds with full operational ...


Circulation, Sediment Concentration And Oxygen Depletion In The Tidal Ems River, Stefan A. Talke, Huib E. De Swart Jan 2011

Circulation, Sediment Concentration And Oxygen Depletion In The Tidal Ems River, Stefan A. Talke, Huib E. De Swart

Civil and Environmental Engineering Faculty Publications and Presentations

We present measurements which show that the tidal Ems River in Germ any is extremely muddy over a 30 km + turbid zone, with fluid mud o f 1-2 m thickness covering the bed with suspended sediment concentrations (SSC) o f greater than 50 kg.m-3. Moreover, we show that these elevated SSC contain large quantities of organic material which deplete dissolved oxygen (DO) and produce summertime hypoxic zones. Using mathematical modeling, we develop simplified representations o f the estuary physics that reproduce the tidally-averaged circulation, SSC distribution, and oxygen depletion. These models show that SSC and oxygen concentrations are ...


Infrared-Based Measurements Of Velocity, Turbulent Kinetic Energy, And Dissipation At The Water Surface In A Tidal River, C. Chris Chickadel, Stefan A. Talke, Alexander R. Horner-Devine, Andrew T. Jessup Jan 2011

Infrared-Based Measurements Of Velocity, Turbulent Kinetic Energy, And Dissipation At The Water Surface In A Tidal River, C. Chris Chickadel, Stefan A. Talke, Alexander R. Horner-Devine, Andrew T. Jessup

Civil and Environmental Engineering Faculty Publications and Presentations

Thermal infrared (IR) based particle image velocimetry (PIV) is used to measure the evolution of velocity, turbulent kinetic energy (TKE), and the TKE dissipation rate at the water surface in the tidally influenced Snohomish River. Patterns of temperature variability in the IR imagery arise from disruption of the cool skin layer and are used to estimate the 2D velocity field. Comparisons of IR based PIV mean velocity made against a collocated acoustic velocimeter demonstrate high correlation (r2 > 0.9). Over a tidal period, surface TKE computed from the IR velocity varies from 10-4 J·kg-1 to 3x10-3 J·kg-1, with ...