Research

Reliable scientific computing for multiscale and multiphysics PDEs: numerical methods, model–data integration, optimization, and scientific machine learning.

Research Vision

I develop reliable scientific-computing methods for multiscale and multiphysics PDEs.

Keywords: finite element methods; multiphysics and coupled systems; inverse problems and data assimilation; optimization and control; scientific machine learning.

Research vision diagram showing five overlapping areas: multiphysics and coupled systems, inverse problems and data assimilation, optimal control, and scientific machine learning, unified by reliable scientific computing and high-fidelity solvers.
A schematic view of the main directions in my research program.

Funded Research and Collaborative Programs

Current support spans trustworthy scientific AI, computational mathematics, multiphysics energy systems, and research training, with prior NSF and DOE awards supporting numerical PDEs, poromechanics, fracture, and subsurface energy.

Current Major Funded Research

Major externally supported projects in which I serve as PI or Co-PI.

  • Department of EnergyDOE Office of Advanced Scientific Computing Research
    (AI for Science)
    09/2026–08/2029
    DE-SC0026871
    From Uncertainty to Trust: A Scalable Stochastic Computing Framework for Uncertainty Reduction in Artificial Intelligence
    PI: Feng Bao (Florida State University), Co-PIs: Sanghyun Lee, Bryan Quaife, Hristo Chipilski (Florida State University). Total budget: $1 million
  • Department of EnergyDOE GENESIS Mission 09/2026–05/2027
    AI-Powered Manufacturing of High Temperature Superconductors for Fusion Energy
    PI: Fumitake Kametani (Florida State University). FSU Co-PI: Sanghyun Lee. Collaborators include researchers from the National High Magnetic Field Laboratory, High Temperature Superconductors, Inc., and Lawrence Berkeley National Laboratory. Total budget: $0.75 million.
  • National Research Foundation of KoreaNRF Basic Science Research Program / Basic Research Lab 07/2026–06/2029
    RS-2026-25505849
    Operator-Composition-Based Theoretical Analysis of Deep Neural Networks: Focusing on the Transformer
    PI: Sunghwan Moon (Kyungpook National University, South Korea), Co-PIs: Sanghyun Lee (Florida State University), B. Kim, J. Kang (Kyungpook National University). Total budget: 1.5 billion won
  • Department of EnergyDOE Science Foundations for the Energy Earthshots 10/2023–10/2027
    DE-SC0024703
    Advanced Multi-Physics Machine Learning for Subsurface Energy Systems Across Scales
    Collaborative DOE project with the University of Texas at El Paso, Florida State University, Sandia National Laboratories, and the University of Utah; Sanghyun Lee serves as Co-PI at Florida State University.
  • National Science FoundationNational Science Foundation DMS 06/2022–01/2027
    Collaborative Research: DMS-2208402
    Physics-Preserving Adaptive Finite Element Methods for Thermo-Poroelasticity
    PI: Sanghyun Lee (Florida State University); collaborative PI: Son-Young Yi (The University of Texas at El Paso).

Research Training and Collaborative Programs

Programs supporting student research, national-laboratory experience, and sustained collaboration.

  • National Science FoundationNational Science Foundation DMS 09/2024–08/2027
    NSF #2349382
    REU Site: Applied Mathematics in Real World Problems
    Senior Personnel: lead project Data Assimilation and Parameter Prediction Algorithms for Subsurface Flows and Simplified Models in Fluid Dynamics
  • National Science FoundationNational Science Foundation DMS 2026–01/2027
    Supplemental: Geothermal INTERN DMS-2621992
    Dear Colleague Letter: Non-Academic Research Internships for Graduate Students in Geothermal Energy
    Jonathan Valyou internship at Sandia National Laboratories (Dr. Hongkyu Yoon).
  • Department of EnergyKyungpook National University 10/2025–09/2030
    Global Matching Lab
    Sanghyun Lee (Florida State University) and Sunghwan Moon (Kyungpook National University, Republic of Korea)

Selected Completed Funding

  • National Science FoundationNational Science Foundation DMS 08/2019–07/2022
    DMS-1913016
    Fluid-filled Fracture Propagation with a Phase-Field Approach in Subsurface by Employing Nonlinear Strain-Limiting Models and Enriched Galerkin Methods
    PI: Sanghyun Lee
  • National Science FoundationNational Science Foundation DMS 06/2024–05/2025
    Supplemental: Geothermal INTERN DMS-2419267
    Dear Colleague Letter: Non-Academic Research Internships for Graduate Students in Geothermal Energy
    Seungmin Lee visited Lawrence Livermore National Laboratory (Dr. Joshua White).
  • National Science FoundationNational Science Foundation DMS 06/2023–05/2024
    Supplemental: Geothermal INTERN DMS-2327841
    Dear Colleague Letter: Non-Academic Research Internships for Graduate Students in Geothermal Energy
    Yi-Yung Yang visited Sandia National Laboratories (Dr. Hongkyu Yoon).
  • Florida State University Multidisciplinary Support 2020–2021
    MDS: #045490
    Studies for Degradation of Lignin-based Biodegradable Plastics to Prevent Marine Debris
  • Florida State University First Year Assistant Professor Program (FYAP) 05/2018–08/2018
    CRC: 041950
    Optimal Error Estimate of Flow Problems with Dirac Sources in Subsurface for Discontinuous and Enriched Galerkin Methods

Current Research Areas

My current research program is organized around six closely connected themes, from structure-preserving numerical PDEs to data-driven and decision-oriented scientific computing.

01 Structure-Preserving Numerical PDEs

Conservation, stability, adaptivity & scalable solvers

Enriched Galerkin finite elements, local conservation, locking-free approximation, bound and entropy preservation, multiscale methods, a posteriori error estimation, adaptivity, and efficient solvers.

Explore this area →

02 Multiphysics, Poromechanics & Fracture

THM/THMC systems & phase-field fracture

Coupled flow, deformation, heat and transport; poroelasticity, thermo-hydro-mechanics, phase-field fracture, evolving interfaces, splitting strategies, and multirate coupling.

Explore this area →

03 Scientific Machine Learning

Operator learning, reduced models & verification

DeepONet and finite-element operator learning, reduced and multi-fidelity models, physics- and structure-guided learning, and verification of learned PDE models.

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04 Inverse Problems & Data Assimilation

Model–data integration, inference & uncertainty

Inverse PDE problems, continuous and ensemble data assimilation, parameter estimation, uncertainty-aware inference, Bayesian computation, and measurement design.

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05 Optimization & Goal-Oriented Computation

Control, adaptivity & decision-making

PDE-constrained optimization, state constraints, goal-oriented error estimation and adaptivity, active-set solvers, reduced models, and decisions under uncertainty.

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06 Energy, Earth & Materials

Subsurface energy, geothermal & fusion materials

Mathematical and computational challenges in subsurface energy systems, geothermal processes, porous-media fracture, and emerging superconducting-material and fusion applications.

Explore this area →

Earlier Research in Computational Fluid Dynamics

Earlier work includes projection methods for incompressible Navier–Stokes equations, level-set methods for multiphase flow, Newtonian and non-Newtonian bouncing jets, and viscous fingering. These pages are retained as an archive of earlier projects, including simulations and visualizations.