Events Calendar

Astani CEE Ph.D. Seminar

Speaker: Dr. Todd Oliver, Institute for Computational Engineering and Sciences (ICES) at UT-Austin

Talk Title: A Framework for Validating Predictions of Unobserved Quantities with Applicatons from Turbulent Flow Similation

Abstract:
In applied science and engineering, computational models are commonly used to make predictions of quantities that are not experimentally observable. Assessing the validity of such predictions, which are fundamentally extrapolations, is challenging but critical. In classical approaches to validation, model outputs for observed quantities are compared to observations to determine if they are consistent. By itself, this consistency only ensures that the model can predict the observed quantities under the conditions of the observations. This limitation dramatically reduces the utility of the
validation effort for decision making because it implies nothing about predictions of unobserved QoIs or for scenarios outside of the range of observations.

This talk will describe a process for validation of extrapolative predictions for models with known sources of error. The process includes stochastic modeling, calibration, validation, and predictive assessment phases where representations of known sources of uncertainty and error are built, informed, and tested. The methodology is applied to a simple spring-mass-damper system to illustrate the process in the simplest possible setting. Finally, some aspects of the process, including calibration and stochastic modeling, are discussed in the context of RANS turbulence modeling.





Biography:

Todd Oliver is a research associate with the Center for Predictive Engineering and Computational Sciences (PECOS) at the Institute for Computational Engineering and Sciences (ICES) at UT-Austin. Dr. Oliver's expertise is in the broad area of computational fluid dynamics with specific focus on statistical methods for the validation of models and predictions. At PECOS he developed predictive tools for the analysis and design of re-entry vehicles.


Host: Dr. Roger Ghanem

Location: Seeley G. Mudd Building (SGM) - 101

Audiences: Everyone Is Invited

Contact: Evangeline Reyes