Tim Colonius
Frank and Ora Lee Marble Professor of Mechanical Engineering
California Institute of Technology
Winner of the 2022 ASME Freeman Scholar Award
Title: Progress and Challenges in the Simulation of Bubbly Cavitating Flows
Abstract: Flow models and numerical methods for multiphase, cavitating flows have benefitted from recent advances in sharp and diffuse interface-capturing schemes, but many challenges remain. Resolving the complex interface and large range of spatiotemporal scales associated with cavitation strains existing algorithms and computational resources. We review formulations for multiphase/multicomponent flows that involve large changes in volume, including methods that explicitly resolve the material interface, and ones that model the mixture as either homogeneous or as a dilute dispersion of spherical bubbles. For resolved-interface modeling, the seemingly simple test case of a single collapsing spherical bubble—solved without assuming symmetry on a three-dimensional grid—represents a successful application of interface capturing techniques, but it also highlights ongoing pathologies in the numerical methods and the extreme challenges of fully resolving the physics. Closure models, in the form of sub-grid-scale bubble modeling and hybrid, large-eddy-simulation-like approaches, can reduce this computational burden. We show how data-driven/machine-learned closure models can harness information from experiments and interface-resolved simulations to improve closures and develop accurate, general-purpose cavitation models. The models discussed are illustrated through application to cavitation and bubble dynamics in therapeutic ultrasound and other medical applications.
Biography: Tim Colonius is the Frank and Ora Lee Marble Professor of Mechanical Engineering at the California Institute of Technology. He received his B.S. from the University of Michigan in 1987 and M.S and Ph.D. in Mechanical Engineering from Stanford University in 1988 and 1994, respectively. He and his research team use numerical simulations to study a range of problems in fluid dynamics, including aeroacoustics, flow control, instabilities, shock waves, and bubble dynamics. Prof. Colonius also investigates medical applications of ultrasound, and is a member of the Medical Engineering faculty at Caltech. He is a Fellow of the American Physical Society and the Acoustical Society of America, He was the recipient of the 2018 AIAA Aeroacoustics Award and the 2022 APS-DFD Stanley Corrsin Award.
Prof. Dr.-Ing. Paul Uwe Thamsen
Professor Fluid System Dynamics
Technical University Berlin
Winner of the 2022 ASME Henry R. Worthington Medal
Title: Research on Centrifugal Pumps Over the Course of Time
Abstract: The research on centrifugal pumps in the last decades moved from specific topics around the pump design more and more to a holistic approaches of the complete pumping system. The presentation will bridge the research questions starting from specific pump improvements, e.g. cavitation bores in a single blade pump destroying cloud cavitation or a special semi-axial design for constant power consumption to the complete design of pumping stations, diagnostic with active reactions and digitalization. Nowadays, pump research participates actively in solving the great challenges from energy, water and climate impact.
Biography: Prof. Dr.-Ing. Paul Uwe Thamsen's education (1980-1992) at Pfleiderer-Institute Braunschweig focused on: pump design, experimental investigations, cavitation measurements, submersible pump development finalized in doctorate research on Operational Behavior of Submersible Pumps with Inlet Distortions. During the industrial time (1992 – 2003) at Pleuger Worthington GmbH in Hamburg (Ingersoll Dresser Pumps /Flowserve), his responsibility was for R&D, engineering, marketing and sales, general management - always involved in technical development as a hydraulic/technical expert for a lot of projects. Final position was general manager and technical director for submersible pumps worldwide. During this time, they developed a couple of successful new pump lines and built challenging projects (e.g. large water projects, multiphase subsea, mining, offshore).
Since 2003, he professor for fluidsystemdynamics at Technical University Berlin, focusing on fluid mechanic, fluid flow machines and fluid infrastructures. Main research topics are on centrifugal pumps, water and wastewater, automation & digitalization and medical applications. A strong cooperation with industry results in innovative products and new control methods for pump operation. A lot of results are published in new standards for pumping station design a pumping infrastructure in the field of wastewater pumping.
Yassin A Hassan
University Distinguished Professor, Regents Professor and the L.F. Peterson '36 Chair II in Engineering
Texas A&M University
Winner of the 2022 ASME Fluids Engineering Award
Title: High Resolution Experiments for Modeling and Simulation: from Nuclear Applications to COVID-19
Biography: Prior to joining Texas A&M September 1986, Yassin worked for seven years at Nuclear Power Division, Babcock & Wilcox Company, Lynchburg, Virginia, where he conducted several thermal hydraulic analyses and undertook development of several computational techniques. He has performed experimental and computational studies of advanced reactors (gas cooled reactors, liquid metal, molten salt and SMR). Participated in resolving the Generic Safety Issue (GSI-191) for the South Texas Project Nuclear Operating Plant. He is the Director of the Center for Advanced Small Modular and Microreactors (CASMR). He is appointed a member of the Civil Nuclear Trade Advisory committee by Honorable Commerce Secretary Gina Raimondo, May 4, 2021. He graduated and advised 60 PhD and 112 MS graduate students. He has co-authored with his students more than 600 refereed publications in technical journals and conference proceedings. He delivered more than 150 plenary and invited presentations.