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Full-Text Articles in Engineering
Least-Squares Finite-Element Scheme For The Lattice Boltzmann Method On An Unstructured Mesh, Yusong Li, Eugene J. Leboeuf, P. K. Basu
Least-Squares Finite-Element Scheme For The Lattice Boltzmann Method On An Unstructured Mesh, Yusong Li, Eugene J. Leboeuf, P. K. Basu
Department of Civil and Environmental Engineering: Faculty Publications
A numerical model of the lattice Boltzmann method (LBM) utilizing least-squares finite-element method in space and the Crank–Nicolson method in time is developed. This method is able to solve fluid flow in domains that contain complex or irregular geometric boundaries by using the flexibility and numerical stability of a finite-element method, while employing accurate least-squares optimization. Fourth-order accuracy in space and second-order accuracy in time are derived for a pure advection equation on a uniform mesh; while high stability is implied from a von Neumann linearized stability analysis. Implemented on unstructured mesh through an innovative element-by-element approach, the proposed method …
Modified Log–Wake Law For Zero-Pressure-Gradient Turbulent Boundary Layers, Junke Guo, Pierre Y. Julien, Meroney N. Meroney
Modified Log–Wake Law For Zero-Pressure-Gradient Turbulent Boundary Layers, Junke Guo, Pierre Y. Julien, Meroney N. Meroney
Department of Civil and Environmental Engineering: Faculty Publications
This paper shows that the turbulent velocity profile for zero-pressure-gradient boundary layers is affected by the wall shear stress and convective inertia. The effect of the wall shear stress is dominant in the so-called overlap region and can be described by a logarithmic law in which the von Karman constant is about 0.4 while the additive constant depends on a Reynolds number. The effect of the convective inertia can be described by the Coles wake law with a constant wake strength about 0.76.A cubic correction term is introduced to satisfy the zero velocity gradient requirement at the boundary layer edge. …
Effects Of Long-Term Wastewater Application On Chemical Properties And Phosphorus Adsorption Capacity In Soils Of A Wastewater Land Treatment System, Cong Hu, Tian Zhang, Yong Huang, Mohamed F. Dahab, Rao Surampalli
Effects Of Long-Term Wastewater Application On Chemical Properties And Phosphorus Adsorption Capacity In Soils Of A Wastewater Land Treatment System, Cong Hu, Tian Zhang, Yong Huang, Mohamed F. Dahab, Rao Surampalli
Department of Civil and Environmental Engineering: Faculty Publications
The buildup of phosphorus (P) in the soil is a major factor limiting the operating life of a wastewater land treatment system. In this study, we evaluated changes of chemical properties, P profiles, and adsorption isotherms in the soils of a Muskegon wastewater land treatment system, which has received wastewater for ~30 years. It was found that the pH in the 15-cm topsoil increased from ~5-6 in 1973 to ~7.4-7.8 in 2003; a large amount of salt (e.g., Ca, Mg) in wastewater was adsorbed by the soil; the soil Al content (either exchangeable or oxalate extractable) decreased, while the oxalate-extractable …
High-Impact, Energy-Absorbing Vehicle Barrier System: U.S. Patent No. Us 6,926,461 B1, Ronald K. Faller, Dean L. Sicking, John R. Rohde, A. Keller, Robert W. Bielenberg, James C. Holloway, Kenneth H. Addink, Karla A. Polivka
High-Impact, Energy-Absorbing Vehicle Barrier System: U.S. Patent No. Us 6,926,461 B1, Ronald K. Faller, Dean L. Sicking, John R. Rohde, A. Keller, Robert W. Bielenberg, James C. Holloway, Kenneth H. Addink, Karla A. Polivka
Department of Civil and Environmental Engineering: Faculty Publications
A high-impact, energy-absorbing vehicle barrier system generally includes a substantially rigid outer containment wall coupled via cable restraint assemblies with an energy-absorbing inner impact wall, and energy-absorbing cartridges strategically positioned between the impact wall and containment-wall: The impact wall is constructed of a number of rectangular tubes coupled with one another to presents a substantially smooth, uniform surface to passing vehicles. The energy-absorbing cartridges generally consist of a number of foam sheets which compress and crush between the containment wall and impact wall to absorb energy from an errant vehicle striking the face of the impact wall, while the deflection …
Stochastic Modeling Of The Permeability Of Randomly Generated Porous Media, Yusong Li, Eugene Leboeuf, P. K. Basu, Sankaran Mahadevan
Stochastic Modeling Of The Permeability Of Randomly Generated Porous Media, Yusong Li, Eugene Leboeuf, P. K. Basu, Sankaran Mahadevan
Department of Civil and Environmental Engineering: Faculty Publications
Permeability of porous media in subsurface environments is subject to potentially large uncertainties due to the heterogeneity of natural systems. In this study, a first-order reliability method (FORM) is combined with a lattice Boltzmann method (LBM) to estimate the permeability of randomly generated porous media. The proposed procedure provides an increased ease of addressing complex pore structures by employing LBM to model fluid flow, while inheriting the computational efficiency from FORM. Macroscale- equivalent permeability can thus be estimated with significantly reduced computational efforts, while maintaining a connection to the complex microscale fluid dynamics within a pore structure environment. Implemented on …
Composite Action System And Method: U.S. Patent No. Us 6,871,462 B2, Atorod Azizinamini
Composite Action System And Method: U.S. Patent No. Us 6,871,462 B2, Atorod Azizinamini
Department of Civil and Environmental Engineering: Faculty Publications
The present invention provides a composite action system and a method for fabricating the same to meet OSHA safety requirements and allow for welding off the work site. An improved structural system achieves the desired composite behavior by providing one or more structural members, plates coupled with the structural members, transverse reinforcing members passing through apertures in the plates, and additional reinforcing members positioned parallel and transverse to the structural members to provide an interlocking composite action between the structural members, reinforcing members, and concrete.
Shear Stress In Smooth Rectangular Open-Channel Flows, Junke Guo, Pierre Y. Julien
Shear Stress In Smooth Rectangular Open-Channel Flows, Junke Guo, Pierre Y. Julien
Department of Civil and Environmental Engineering: Faculty Publications
The average bed and sidewall shear stresses in smooth rectangular open-channel flows are determined after solving the continuity and momentum equations. The analysis shows that the shear stresses are function of three components: (1) gravitational; (2) secondary flows; and (3) interfacial shear stress. An analytical solution in terms of series expansion is obtained for the case of constant eddy viscosity without secondary currents. In comparison with laboratory measurements, it slightly overestimates the average bed shear stress measurements but underestimates the average sidewall shear stress by 17% when the width–depth ratio becomes large. A second approximation is formulated after introducing two …
Configuration Methodology For Traffic-Responsive Plan Selection: A Global Perspective, Montasir M. Abbas, Nadeem A. Chaudhary, Geza Pesti, Anuj Sharma
Configuration Methodology For Traffic-Responsive Plan Selection: A Global Perspective, Montasir M. Abbas, Nadeem A. Chaudhary, Geza Pesti, Anuj Sharma
Department of Civil and Environmental Engineering: Faculty Publications
Although several studies have shown the potential great benefits of traffic-responsive plan selection (TRPS) control, time-of-day operation continues to be the primary method used to select patterns for signal control applications. This practice could be largely attributed to the minimal guidelines available on the setup of the TRPS mode. An innovative framework for TRPS system setup is provided, and guidelines for implementing TRPS in a simplified manner are shown. The guidelines, developed at Texas Transportation Institute (TTI), use a comprehensive approach that incorporates a multiobjective evolutionary algorithm and a supervised discriminant analysis. Engineers can directly implement the guidelines presented as …
Optimization Of Time Of Day Plan Scheduling Using A Multi-Objective Evolutionary Algorithm, Montasir M. Abbas, Anuj Sharma
Optimization Of Time Of Day Plan Scheduling Using A Multi-Objective Evolutionary Algorithm, Montasir M. Abbas, Anuj Sharma
Department of Civil and Environmental Engineering: Faculty Publications
Coordinating traffic signals can provide great savings to motorists in terms of reduced delays and number of vehicular stops. In order to maximize benefits, engineers need to use a mechanism by which the most optimal timing plans are activated when the traffic patterns change. Common ways of accomplishing this need is by using Time of Day (TOD) plan scheduling, or Traffic Responsive Plan Selection (TRPS). Out of the two modes, the TOD mode is by far the most common. Engineers, however, typically use their judgment to determine the TOD plan scheduling. Unless traffic patterns change at certain times of the …