Jennifer Franck

Assistant Professor
University of Wisconsin-Madison 

“Fluid Dynamics in the Wake of Bio-Inspired Flows”Abstract: Swimming and flying animals rely on the fluid around them to provide lift or thrust forces, leaving behind a distinct vortex wake in the fluid. The structure and size of the vortex wake is a blueprint of the animal’s kinematic trajectory, holding information about the forces and also the size, speed and direction of motion. This talk will introduce two bio-inspired flows, and work towards linking the fluid dynamic wake signature to the underlying dynamics or topography causing the wake. The first example is an oscillating hydrofoil, which can be operated to generate energy through lift generation, in the same manner as flapping birds or bats. The second example is flow over a seal whisker, a surprisingly complex undulated geometry thought to provide seals with exceptional tracking abilities in water. For both projects the unsteady fluid dynamic mechanisms are explored through numerical simulations, proving insight for future engineering design and control of bio-mimetic systems.

Bio: Jennifer Franck is an Assistant Professor in the Department of Engineering Physics at the University of Wisconsin-Madison. She leads the Computational Flow Physics and Modeling Lab, using computational fluid dynamics (CFD) techniques to explore the flow physics of unsteady and turbulent flows. Ongoing research projects are in the areas of bio-inspired flows and the fluid dynamics of renewable energy systems. Prior to joining the UW-Madison faculty in 2018, she was faculty at Brown University where she was recognized with numerous teaching and mentoring awards. She received her undergraduate degree in Aerospace Engineering from University of Virginia, followed by a M.S. and Ph.D. from California Institute of Technology. Following her PhD, she was awarded an NSF Postdoctoral Fellowship hosted at Brown University to computationally explore fluid dynamics mechanics of flapping flight. Her research is currently funded by NSF and ARPA-E.

Aaron Morris

Assistant Professor 
Purdue University

“Using Discrete Element Simulations to Bridge Particle and Continuum Flow Scales”Abstract: Particle flows are ubiquitous in nature (e.g., avalanches, volcanic eruptions, and planetary rings) and are common in processes used by a wide range of industries, such as energy, agriculture, and chemical processing. Despite the prevalence of processes involving particle transport, the behavior of flowing particles is often poorly understood, and improved predictive capabilities are needed. Particle flows tend to be chaotic, and subtleties that occur at small length scales (e.g., a single particle) can significantly impact large-scale flow behavior. As such, empirical tools can be unreliable when extrapolated to new systems, and fundamental modeling approaches will play a key role in developing better design tools that do not rely solely on costly experimentation. The discrete element method is a powerful modeling tool that tracks all individual particles in a system. However, the method is limited to relatively small-scale systems consisting of several million particles. For perspective, one cup of sand contains approximately 10 million particles. Despite the computational limitations of the discrete element method, it can be used to gain insight and develop constitutive relations for continuum scales. This presentation will discuss two applications where discrete element simulations are upscaled. In the first application, discrete element simulations are used to elucidate heat transfer mechanisms to flowing particles and develop continuum closures suitable for modeling large scale systems. In the second application, discrete element simulations are used to help develop a kinetic theory for complex granular flows with non-spherical particles.

Bio: Dr. Morris joined Purdue University as an assistant professor in January 2017 and his research group develops models to better understand and predict gas-solid and granular flows. His research group uses a variety of simulation techniques, but focuses on discrete element modeling, direct simulation Monte Carlo methods, and continuum modeling. The theme of his research is to bridge the understanding of how physics that occur at particle scales affect macroscale behavior. His past research projects involve using the discrete element method to simulate the heat transfer to flowing particles, Monte Carlo methods to simulate gas-solid flows in industrially relevant systems, fluidized systems with homogeneous and heterogeneous chemical reactions, spray drying, and rarefied gas dynamics and dust dispersal. Prior to joining Purdue University, Dr. Morris was a postdoctoral fellow at the Department of Energy National Energy Technology Laboratory from 2015 to 2016 and was a postdoc in the Hrenya Research Group at the University of Colorado Boulder. Dr. Morris earned his Ph.D. from the University of Texas at Austin in 2012, examining the interactions between rocket exhaust plumes and the dusty lunar surface.