Warren Distinguished Lecture Series

Anu Ramaswami
Charles M. Denny Jr. Chair Professor of Science Technology & Public Policy
Hubert H. Humphrey School of Public Affairs
University of Minnesota

Abstract

Cities would not function without infrastructures that provide water, energy, food, shelter, waste management and mobility services to more than half the world's people living in them today.

How do people, infrastructures and the natural system interact with each other across spatial scale to shape multiple sustainability outcomes for cities – including environmental, economic, risk/resiliency and public health outcomes? How can we better design our urban infrastructure systems to achieve these multiple sustainability outcomes? Who governs the design and diffusion of these more sustainable infrastructure systems in society – and what motivates them to do so (or not)?

These important questions will be explored using a novel social-ecological- infrastructural systems (SEIS) framework for developing sustainable, healthy and climate-resilient cities. The framework will be applied to describe recent efforts to measure and mitigate greenhouse gas (GHG) emissions associated with cities, using a portfolio of interventions including: infrastructure design/technology interventions, as well as behavior change and policy interventions.

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Vasco Varduhn
Department of Civil and Environmental Engineering
Technische Universitäät, Munchen

Abstract

Urban flooding scenarios are of great interest to engineers and city planners. In this talk, an approach is introduced, which focuses on the numerical simulation of the fluid behavior and its impact on multiple scales, ranging from a city wide scope to the effect on fine construction details.

In order to accurately simulate flooding events in urban regions, many aspects have to be taken into account. The data basis covers a highly detailed terrain description, combined with the fully detailed representation of constructions such as buildings, bridges and infrastructure objects. Furthermore the interaction of sewer networks is investigated, as they can have strong impact on the fluid behavior.

This setting introduces a complex simulation scenario. The different geometric scales make multi-resolution approaches inevitable, also the dimensionality of the numerical simulation varies. This ranges from a 1D scheme for the effects of pipe network interaction to 2D and 3D schemes for over ground water flow and behavior around and inside of buildings.

In order to bring all this together, techniques from scientific computing, high performance computing and scientific visualization are applied and presented for the whole simulation pipeline, including a detailed investigation of simulation results for answering engineering relevant questions.

Note: this lecture will not be available via streaming and will not be recorded

Jaydeep Bardhan
Department of Electrical and Computer Engineering
Northeastern University

Abstract

Society has much to gain from understanding the design principles that underlie protein function and regulation, and much research focuses on the biologically crucial electrostatic interactions between charged chemical groups. This presentation will introduce how the trusty old Poisson equation—this year marks the 200th anniversary of Poisson's seminal paper—helps explain biology, and how biology, in turn, is driving exciting new developments in mathematics and computational science. In particular, boundary-element method (BEM) simulations offer an appealing alternative to the finite-element method (FEM) ones that are popular throughout engineering and science. After a gentle introduction to BEM simulation and its many advantages for multiscale simulations of complex systems, the presentation will describe the Generalized-Born (GB) model, a simple approximation of the Poisson equation that is widely used in protein simulations. The GB approach suggests new ways to solve complicated PDEs quickly and accurately on GPUs and supercomputers, even for macroscopic problems that have nothing to do with proteins!

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Michael Triantafyllou
William I. Koch Professor of Marine Technology, Professor of Mechanical and Ocean Engineering and Director, Center for Ocean Engineering, Massachusetts Institute of Technology

Schedule

3:30 - Welcome and Award Presentation – Fotis Sotiropoulos, James L. Record Professor of
Civil Engineering and Director, St. Anthony Falls Laboratory; Joseph Labuz, MSES/Miles
Kersten Professor and Interim Department Head, Department of Civil Engineering

3:40 - Recipient Remarks – Michael Cardiff, Assistant Professor, Department of Geoscience,
University of Wisconsin-Madison

3:50 - Keynote Presentation – “Vanishing and Shrinking Bodies, Global Vorticity Shedding, and
Biomimetics” – Michael Triantafyllou, William I. Koch Professor of Marine Technology,
Professor of Mechanical and Ocean Engineering and Director, Center for Ocean
Engineering, Massachusetts Institute of Technology

4:35 - Question and Answer

4:45 - Reception

Abstract

For bodies that move within a fluid and undergo rapid shape changes, boundary layer vorticity can be shed simultaneously from large sections of their surface, in what is termed global vorticity shedding, while kinetic energy may be lost to the fluid or recovered. Examples include foils and bodies retracted fast from the fluid, bodies of collapsing volume, and vanishing or phase-changing bodies and cavities. This rapid transition of vorticity from the boundary layer to the fluid is in sharp contrast to the flow separation from isolated areas of a body, which results in a gradual formation of large-scale structures.

Global vorticity shedding is reviewed as a means for generating large forces and controlling the flow around unsteadily moving bodies. We highlight the concepts by studying the ultra-fast escape of an octopus-like body, which combines several hydrodynamic mechanisms, viscous and inviscid, to achieve a remarkable performance, outperforming any other jet-propelled system: Separation elimination through rapid deflation, added mass energy recovery, and optimized energy storing in the fluid and recovery.

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Ross Corotis
The Department of Civil, Environmental, and Architectural Engineering, University of Colorado-Boulder

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Abstract

The cost of natural disasters continues to rise around the world, in part because of population growth, urbanization and the pressures they place on land use, and in part because policy makers continue to undervalue natural hazard risk in long-term planning. The shortcoming in reducing the vulnerability of infrastructure lies partly with engineers and risk professionals, who must be aware of public perceptions of risk and political process rationality, which present inherent incompatibilities.  Engineers need to know which measures of risk are most meaningful or relevant to decision makers, and then be able to communicate those risks, and the costs and benefits of mitigation, in concise, credible, meaningful terms. A major challenge is demonstrating a need to those who may have difficulty extrapolating personal experiences to low-probability, high-consequence events. Research and examination of case studies has led to the identification of five key issues central to effective risk and retrofit communication: (1) public risk perception, (2) public participation in hazard mitigation planning, (3) incorporation of community values, (4) incompatibility of political motivation and long-term planning, and (5) financing of risk and return. These issues provide a framework for understanding the challenges to promoting retrofit and for developing communication strategies to overcome them.

About the Speaker

Ross B. Corotis, PE, NAE, is the Denver Business Challenge Professor of Engineering at the University of Colorado at Boulder.  He earned his S.B., S.M. and Ph.D. degrees from MIT, was on the faculty of Northwestern University for 11 years, established the Department of Civil Engineering at The Johns Hopkins University, where he was also Associate Dean, and was Dean of the College of Engineering and Applied Science in Boulder.  His research interests are in the application of probabilistic concepts and decision perceptions for civil engineering problems, and in particular to societal tradeoffs for hazards in the built environment.  He was Editor of the ASCE Journal of Engineering Mechanics and the international journal Structural Safety, and chaired the Executive Committee of the International Association for Structural Safety and Reliability.  He has won numerous research, teaching and service awards, and chaired professional committees on structural safety for ASCE and ACI.  For The National Academies he serves on the Board on Infrastructure and the Constructed Environment (and previously on the Building Research Board), and is the founding chair of The National Academies Assessment Committee for NIST.  He previously served on the Academies’ steering committee of the Disasters Roundtable, and chaired the Assessment Panel for the NIST Building and Fire Research Laboratory, and is the Past Chair of the Civil Engineering Section of the National Academy of Engineering.  He is a registered professional engineer in Illinois, Maryland and Colorado, a registered structural engineer in Illinois, and a Distinguished Member of ASCE. In 2007-2008 he served as science advisor at the Department of State in Washington, DC.  He is the author of more than 200 publications.

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Giuseppe Buscarnera
Department of Civil and Environmental Engineering, Northwestern University

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Abstract

The talk focuses on the application of the theory of material stability to the analysis of unsaturated shallow slopes. As is well-known, loose unsaturated deposits are prone to develop inelastic compaction upon saturation, a process commonly referred to as "wetting-collapse". The purpose of the talk is to elucidate the mechanical nature of such collapses and explore their relation with the initiation of flowslides. The presentation discusses a unified modeling framework based on: (i) a theoretical framework for identifying material instabilities in unsaturated soils, (i) a constitutive model capable of reproducing liquefaction processes and (iii) a simplified methodology for quantifying triggering perturbations. The presentation illustrates the key role played by specific properties, such as those that govern the coupling between solid skeleton and fluid-retention mechanisms. Such couplings imply that saturation-induced instabilities are prone to occur within a specific range of slope angles, that depends on the consititutive properties of the soil and the thickness of the deposit. The analyses suggest that, within such a range of inclinations, flow failures can be triggered by a chain process consisting of volumetric collapse, sudden saturation of the pores and, eventually, catastrophic liquefaction of the deposit.

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Desmond Lawler
Department of Civil, Architectural and Environmental Engineering, UT-Austin

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Abstract

Particle treatment processes are at the heart of both (surface) drinking water treatment and wastewater treatment. Many contaminants in water and wastewater are particles, are made into particles, or are removed by attaching to particles. Throughout my career, I have been pursuing the links between fundamental particle properties (particularly size distributions, but also shape, surface charge, and adsorbed materials such as natural organic matter) and the optimal design and operation of particle processes. Current work includes considering the fate of nanoparticles in conventional particle processes. Flocculation, precipitation, gravity removal processes (sedimentation, flotation, thickening), granular media filtration, and dewatering have all been the focus of my work with various Master’s and Ph.D. students. In addition, we have studied the linkages of these processes to one another in conventional water treatment plants. A few of the key insights from this work include the relative insignificance of the velocity gradient in determining the success of flocculation, the importance of flow patterns in open tanks such as flocculation and sedimentation reactors, the role of detachment in the effluent water quality from granular media filters, and a design methodology for granular media filters that could save piloting costs.

Biography

Desmond Lawler is the Nasser I. Al-Rashid Chair in Civil Engineering and a member of the Academy of Distinguished Teachers at the University of Texas. Lawler’s research and teaching focus on physical/chemical treatment processes for water and wastewater, with greater emphasis on drinking water treatment. Throughout his career, he has studied particle removal processes and more recently has been studying desalination and processes for the removal of pharmaceuticals and personal care products. He served as the Secretary of AEESP for two years early in his career, and has been a board member of the Water Science and Research Division of AWWA for the past several years. He is a member of the Drinking Water Committee of the Science Advisory Board of the USEPA. Des has received several teaching awards at UT and his contributions to research and education have been recognized with major awards by AWWA, WEF, and AMTA. His 75 MS graduates are productive throughout the water and wastewater field, and 14 of his 20 PhD graduates are academicians.

Andrew Norris
Department of of Mechanical Engineering, Rutgers University

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Abstract

The concept of transformation optics is to take a region of space and replace it with material occupying another region that has the same optical properties as the original. This opens up the possibility for cloaking: by replacing, e.g. a spherical region by a shell at its outer boundary it makes the interior invisible. The talk will discuss transformations that show these effects in acoustics and in elasticity.  It will be shown that the acoustic material after transformation is not unique, unlike the case for electromagnetic waves. The non-uniqueness means that the same effects can be achieved using either anisotropic density or pentamode materials (which will be defined). Both of these unusual types of materials will be defined in detail in the talk, with the emphasis on pentamode materials (PM). Recent work on the design of PM-based devices will be described. This includes the concept of Metal Water which replaces water by an equivalent metal foam that has the acoustic wave speed and impedance of water, and low shear stiffness. By reshaping the material the empty spaces in the foam can be combined to give a large “cloaked” region. This type of material makes acoustic cloaking easy to understand, and also potentially realizable. The Metal Water metamaterial also has interesting Bloch wave properties that could have application for negative index of refraction devices, such as the superlens.

Lorenz G. Straub Award Ceremony

S. "Bala" Balachandar
Department of Mechanical and Aerospace Engineering, University of Florida

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Abstract

Penetration of one material into another is a fundamental fluid mechanical process that can be observed all around us in many industrial and environmental applications. Filling/emptying pipelines, coating flows, falling films and sedimentation fronts are some industrial applications. Tsunamis, volcanic plumes, lava and pyroclastic flows, dust storms, powder snow avalanches, submarine turbidity currents and supernovae offer fascinating examples of advancing material fronts. This talk will introduce the concept of gravity currents, where the density difference between the propagating and the ambient materials drives the flow. The examples mentioned above include both scalar and particulate gravity currents, where in the former the density difference is due to temperature or salinity, while in the later suspended particles contribute to density difference. Particular attention will be paid to the front velocity and simple theoretical models that attempts to predict it. The propagating fronts undergo Rayleigh-Taylor, Lobe-and-cleft and Kelvin-Helmholtz instabilities, giving rise to fascinating pathways to turbulence.

One particular example we will consider in greater detail is the sustained propagation of submarine turbidity currents, whose propagation depends on an interesting interplay between suspended particles and turbulence. The suspended particles drive the flow and are the source of turbulence in a turbidity current, while the flow turbulence enables resuspension of particles from the bed. If resuspension dominates over deposition the intensity of the current can increase, thereby further increasing resuspension and resulting in a runaway current. On the other hand, stable stratification due to suspended sediment concentration can damp and even kill turbulence. Then deposition dominates over resuspension and the current could laminarize resulting in massive deposits.

In this talk we present results that indicate the existence of conditions for the total damping of the nearbed turbulence. Under these conditions, sediment in suspension rains out passively on the bed, even though the upper layer may remain turbulent. The above scenario provides a reasonable (but not unique) explanation for the formation of massive turbidities that have recently been reported from field observations.

Cliff Davidson
Civil and Environmental Engineering Department, Syracuse University

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Abstract

Research on exchange processes between the atmosphere and surfaces are discussed in this seminar, focusing on three specific case studies. In the first, a mass balance for airborne lead in the South Coast Air Basin (SOCAB) of California is presented, using emission inventory data and airborne concentration data on record at the California Air Resources Board. The mass balance results suggest that significant amounts of airborne lead measured currently in the SOCAB result from resuspension of soil originally contaminated by lead during the decades of leaded gasoline use. In the second case study, damage to limestone buildings by atmospheric pollutants is explored through modeling and measurement of a limestone building in Pittsburgh, PA. Results suggest that pollutants weaken the limestone surface which enables subsequent wind-driven rain to erode the surface. The erosion can continue over many years. In the third case study, chemicals in the Greenland Ice Sheet are examined to determine their origin; results suggest that long- range transport of both natural and anthropogenic pollutants are responsible for much of the chemical content in the ice sheet, and that some specific events can be traced back to their origins in the mid-latitudes.

About the Presenter

Cliff Davidson is the Thomas and Colleen Wilmot Professor at Syracuse University in Syracuse, NY. He currently holds appointments in the Civil and Environmental Engineering Department and at the Syracuse Center of Excellence in Environmental and Energy Systems. He received his B.S. in Electrical Engineering from Carnegie Mellon University, and his M.S. and Ph.D. degrees in Environmental Engineering Science from California Institute of Technology. Following his PhD, he joined the Carnegie Mellon faculty in the Department of Civil and Environmental Engineering and the Department of Engineering and Public Policy where he served for 33 years. He joined Syracuse University in 2010. Davidson has written and edited a number of books, has over 100 articles in refereed journals, and was President of the American Association for Aerosol Research during 1999-2000. He is the Founding Director of the Center for Sustainable Engineering, a partnership among Carnegie Mellon, University of Texas at Austin, Arizona State University, Georgia Institute of Technology, and Syracuse University.