A brief review of Reduced Order Models using intrusive and non-intrusive techniques
Guglielmo Padula, Michele Girfoglio, Gianluigi Rozza
TL;DR
The paper surveys reduced order modeling approaches for parameterized PDEs, contrasting intrusive Galerkin ROMs with non-intrusive data-driven surrogates such as PINN, DDNN, RBF, DMD, and GPR, and discusses geometry parametrization via FFD and dimensionality reduction via Active Subspaces. It demonstrates that online speedups up to $10^5$ are achievable, with method performance varying by problem type (e.g., DMD+RBF accuracy in fluids, POD-Galerkin with larger RBs for cylinders, RBF on geometry). Through academic benchmarks (lid-driven cavity, flow past a cylinder, Stanford Bunny) and an industrial refrigerator case, the work illustrates the breadth of ROM techniques and their potential for real-time control and optimization in engineering contexts.
Abstract
Reduced Order Models (ROMs) have gained a great attention by the scientific community in the last years thanks to their capabilities of significantly reducing the computational cost of the numerical simulations, which is a crucial objective in applications like real time control and shape optimization. This contribution aims to provide a brief overview about such a topic. We discuss both an intrusive framework based on a Galerkin projection technique and non-intrusive approaches, including Physics Informed Neural Networks (PINN), purely Data-Driven Neural Networks (DDNN), Radial Basis Functions (RBF), Dynamic Mode Decomposition (DMD) and Gaussian Process Regression (GPR). We also briefly mention geometrical parametrization and dimensionality reduction methods like Active Subspaces (AS). Then we present some results related to academic test cases as well as a preliminary investigation related to an industrial application.
