# Modeling and Simulation Group Meeting Old

#### Two Research Talks

**Speaker:**
Mariya Savinov, Yu-hsuan Shih

**Location:**
Warren Weaver Hall 1314

**Date:**
Thursday, December 10, 2020, 12:30 p.m.

**Synopsis:**

*Mariya will discuss oscillating systems with flexible periods, as those observed in fireflies. Motivated by a recent forced oscillator model of Loehr et al., we explored the behaviors of a pair of two-dimensional maps with free-running phase and period, focusing on characterizing the stability of N:M locking regimes (in which an oscillator produces N cycles for M stimulus cycles). Even with the inclusion of a natural period (a common quality of biological oscillating systems), we find that there is a great deal of multi-stability and the basins of attraction can be complex and riddled. Yu-hsuan will introduce a viscoplastic rheology that can be used to model localization through a yield stress, e.g., in solid earth or sea ice applications. Then, she will present a novel Newton method for solving the nonlinear Stokes flow equations with viscoplastic rheology, which is observed to converge much faster and robustly than traditional fixed point and standard Newton methods.*