DATE:

Friday, May 7, 2021

TIME:

3:30 PM

LOCATION:

Virtual Zoom Conference

SPEAKER:

Dr. Amanda Howard, Mathematician, Advanced computing, mathematics, and data, Pacific Northwest National Laboratory

ABSTRACT:

This talk will introduce non-local mathematical models for two phase (fluid/fluid and fluid/solid) systems. We will discuss the mathematical basis of non-local models, and their role in modeling non Newtonian fluids where local models cannot capture all effects. First, we propose a non-local model for surface tension obtained in the form of an integral of a molecular-force-like function added to the Navier Stokes momentum conservation equation for multiphase fluid flows. We demonstrate that our model recovers both microscale and macroscale features of multiphase flow, eliminating the need for expensive hybrid MD-NS models, and provides strong advantages for modeling multiphase flows at length scales not feasible with MD simulations. Next, we extend the physics-informed neural network (PINN) method to learn a non-local viscosity model for a suspension of spherical particles using only velocity measurements. The PINN-inferred viscosity models agree with the empirical models for shear rates with large absolute values but deviate for shear rates near zero where the analytical models have an unphysical singularity.

Bio: Amanda Howard is a mathematician at Pacific Northwest National Laboratory. Her research interests include numerical methods for multiphase flows, including surface tension models and models for fluid/solid flows, and physics-informed machine learning. She received her PhD in 2018 from Brown University in Applied Mathematics, where she was an NSF Graduate Research Fellow and received the Graduate Student Contribution to Community Life Award for her contributions towards increasing diversity within the mathematics community at Brown.

Presenter Website

Department Link

HOST:

Marta Miletic

VIDEO: