Research

My research interests include DG finite element methods, variational inequalities, PDE-constrained optimization, numerical optimization, physics informed machine learning.

Collaborators

Research Projects

Parabolic variational inequality

By utilizing a symmetric dual-wind DG (DWDG) spatial discretization and a backward Euler temporal discretization, we proposed a fully discrete scheme designed to solve a parabolic variational inequality. We also determined the rate of convergence of the error in space and time in suitable norms.

Numerical solution for numerical experiment 1: Zero Obstable Problem
Numerical Solution
Contact sets for numerical experiment 1: Zero Obstable Problem
Contact set $\Omega_0(t)$
Read more

Steady convection-diffusion equation in the convection dominated regime

We proposed and analyzed a numerically stable and convergent scheme for the convection-diffusion (CD) equation in the convection-dominated regime and derived a local order of convergence of $O(ℎ^{1.5})$ whenever the exact solution is of $𝐻^2(\Omega)$ regularity. The following figures illustrate a comparison between the exact and numerical solution from a particular numerical experiment.

exact solution for numerical experiment 2
Exact Solution
numerical solution for numerical experiment 2
Numerical Solution
Read more

Elliptic optimal control problem with control constraints

We proposed a numerical scheme to reduce an elliptic optimal control problem with control constraints to a finite-dimensional optimization problem with equality and inequality-type constraints and established the order of convergence of the error as we refine the triangulation of the polygonal domain $\Omega \subset \mathbb{R}^2$. The figures below present a comparison between the exact solutions and numerical solutions from a specific numerical experiment.

Picture of exact control
Exact control
Picture of numerical control in P0 spanned space
u_h with $\mathbb{P}_0$ functions
Picture of numerical control in P1 spanned space
u_h with $\mathbb{P}_1$ functions

Picture of exact state
Exact state
Picture of numerical state in P1 spanned space
y_h with $\mathbb{P}_1$ functions
Read more

Peer-Reviewed Publications

Boyana, S. B., Lewis, T., Rapp, A., Zhang, Y. (2023). Convergence analysis of a symmetric dual-wind discontinuous Galerkin method for a parabolic variational inequality. Journal of Computational and Applied Mathematics, 422, 114922.
https://doi.org/10.1016/j.cam.2022.114922
Supported by NSF grants DMS-2111004 (PI: Y. Zhang) and DMS-2111059 (PI: T. Lewis)

Boyana, S. B., Lewis, T., Liu, S., Zhang, Y. (2024). Convergence Analysis of a Novel Discontinuous Galerkin Methods for a Convection Dominated Problem. Journal of Computers and Mathematics with Applications, Volume 175, 2024, Pages 224-235, ISSN 0898-122.
https://doi.org/10.1016/j.camwa.2024.09.027
Supported by NSF grants DMS-2111004 (PI: Y. Zhang), DMS-1929284 (PI: S. Liu) and DMS-2111059 (PI: T. Lewis)

Manuscripts in Preparation

Boyana, S. B., Lewis, T., Zhang, Y. Convergence Analysis of a Symmetric Dual-Wind Discontinuous Galerkin Methods for an Elliptic Optimal Control Problem with Control Constraints.
Supported by NSF grant DMS-2111004 (PI: Y. Zhang)