25 Years of Hydrodynamics CFD: success, impact of HPC, missing physics,
Speaker: Eric Paterson, Virginia Polytechnic Institute and State University
Series: MAE Departmental Seminars
Location: Bowen Hall Room 222
Date/Time: Friday, April 5, 2013, 3:30 p.m. - 4:30 p.m.
Over the past 25 years, the field of computational ship hydrodynamics has made extraordinary progress. Guided by international workshops and collaborative experiments, and supported by growth in high-performance computing (HPC), URANS and hybrid RANS/LES CFD is now capable of solving problems associated with model-scale resistance and propulsion, maneuvering, and seakeeping. However, many multi-physics problems remain unsolved, with discrepancy between theory, experiments, computer models, and full-scale observations. In this talk, I will give a brief overview of this history to motivate my thesis: a) that reductionism, while critical to the basis of engineering knowledge, often blinds us from the truth; b) that open-source computational mechanics software provides a pathway for incorporating missing physics; and c) that the phenomenal growth in HPC is a critical research tool and resource that must be intelligently utilized, and guarded against driving research in unwarranted directions. As an example, I will present the theory of modeling inhomogenous currents (jets and wakes) in the presence of ocean-surface waves. The model is analogous to the physics of Craik-Leibovich vortex forcing which has been attributed as the mechanism for explaining Langmuir circulations. The model has been implemented in CFD solver based upon the open-source library OpenFOAM. Simulation results will be presented for both surface and submerged jets in the presence of both short- and long-wavelength waves. It will be shown that surface waves have a large influence on the advection of the current, and in generation of large-scale circulations.
Dr. Paterson is Professor and Department Head of Aerospace and Ocean Engineering (AOE) at Virginia Polytechnic Institute and State University, a position he has held since August 2012. He earned his PhD in Mechanical Engineering at The University of Iowa, where he was the Hunter Rouse Fellow of Fluid Mechanics at one of the nations oldest and most preeminent fluids laboratories, the Iowa Institute of Hydraulic Research (IIHR). After his graduate studies, he stayed at IIHR as a research engineer to continue his work for the U.S. Navy and the Office of Naval Research, where he was the code architect for CFDSHIP-IOWA, a free-surface RANS code for ship hydrodynamics. In 2001, he moved to Penn State University, where he most recently was Senior Scientist at the Applied Research Laboratory and Professor of Mechanical Engineering. He teaches and performs research in the broad field of fluid mechanics, however, his area of expertise is in computational fluid dynamics (CFD) applied to ship hydrodynamics, heart pumps and cardiovascular flows, renewable energy from terrestrial and offshore wind turbines, and trace detection through biomimicry of canine and fish olfactory systems. Dr. Paterson is active in the Overset CFD and OpenFOAM communities, and was one of the first adopters of OpenFOAM in the USA beginning in 2005. Recent awards include one from the FDA in 2010 for work on the Critical Path CFD Team which developed techniques for assessing device safety, and in 2011 he received the Distinguished Visiting Faculty award from the UKs Royal Academy of Engineering to support collaboration with colleagues at The University of Exeter on tidal turbines and medical imaging techniques for CFD meshing.