Skip to main content

Applied Mathematics and Computation Seminars

Methane bubbles frozen in the ice of Lake Baikal

The AMC seminar is devoted to general topics in applied mathematics and computation. We welcome an interdisciplinary audience and speakers: faculty, researchers, and graduate students from mathematics, geosciences, computer science, engineering, atmospheric sciences, and other disciplines, to attend and present research talks in their fields as well as reaching across multiple fields. Both technical, tutorial, and expository presentations are welcome.

Attendees are encouraged to join the mailing list by sending an email to the organizer (M. Peszynska).

Students attending regularly are encouraged to sign up for (an appropriate section of) seminar credit under MTH 607. Non-OSU participants from outside academe are also encouraged to write an email to the organizers and provide their names and affiliation.

See below for upcoming seminars or access the seminar archive.


Organizers

Malgorzata Peszynska and Ralph E. Showalter.

Timing

Meetings are Fridays at noon.


Improving the accuracy of coupled physics packages in Earth system models

STAG 112

Speaker: Sean Santos

ABSTRACT: Earth system models solve exceedingly complicated multiphysics problems by breaking down the Earth system hierarchically into smaller sub-models (e.g. atmosphere, ocean, land, and sea ice), which are composed of smaller components themselves. This decomposition of an Earth system model (which may require millions of lines of code in its software implementation) into many small modules is a vital part of model development. However, naïve coupling of modular physics packages using first-order methods can significantly reduce model accuracy, or even produce numerical instability. This talk covers two examples from the Energy Exascale Earth System Model (E3SM). First, we will see that “sequential” (Lie-Trotter) splitting is a major source of error for E3SM’s cloud and precipitation physics. We will discuss our evaluation of several proposed alternatives, including Strang splitting and multirate methods. Second, we will see that E3SM is prone to spurious “oscillations” in winds… Read more.


Modeling hypothermia, frostbite, and blood flow regulation with a coupled PDE and ODE system (by Fara) and TBA (by Lilly)

STAG 112

Speaker: Tyler Fara and Jeremy Lily

Abstract (talk by T. Fara) We present a model simulating human body temperature when the extremities (such as hands or feet) are subject to extreme cold, possibly leading to hypothermia. The model involves (1) a PDE for the temperature in the extremity and (2) a reduced/lumped model of temperature in the body core. More specifically, (1) is a parabolic PDE with a nonlinear term modeling the tissue-vascular energy exchange similar to that derived by homogenization by Deuflhard and Hochmuth, and (2) is a constrained, nonlinear ODE. Phenomenologically, the model accounts for (i) the influence of warmed arterial blood on the extremity, (ii) the effect of cooling through the skin on the blood in the microvasculature, (iii) the resulting cooling of the venous blood and (iv) its impact back on the core temperature. Our model also describes (v) the body's attempt to control the loss of heat in the core during hypothermic crisis by vasoconstriction of the microvasculature. Our model is… Read more.


TBA

STAG 112

Speaker: Wei-Xi Boo and Peter Cowal

Read more.


TBA

STAG 112

Speaker: Ricardo Reyes Grimaldo

Read more.


TBA

STAG 112

Speaker: Mark Raleigh

Read more.


Digital Twins for Time Dependent Problems

STAG 112

Speaker: Juan Restrepo

ABSTRACT: A digital twin is a set of algorithms that connect the virtual world to the physical worl in a fully bi-directional way: for example, a predictive digital twin will use physics models, machine learned models, constraints as well as observations to make forecasts. A digital twin used as a controller would yield a virtual prescription, taking into account observations, that prescribes changes in the real world aimed at obtaining a certain desired real world outcome. I will describe ongoing work on developing a digital twin that will become central to an artificial intelligence framework for large scale electric grid resilience via adaptation. BIO: Juan M. Restrepo is a Distinguished Member of the R&D staff and the section head of the mathematics in computation section at Oak Ridge National Laboratory. His research concerns foundational aspects of machine learning and the development of new artificial intelligence algorithms for science. He is a Fellow of the Society of… Read more.


TBA

STAG 112

Speaker: Solomon Yim

Read more.


TBA

STAG 112

Speaker: Eleanor Jenkins

Read more.