Multi-fidelity Surrogate Models

Abstract

Simulation models are treated as black boxes that generate input–output correspondences. Nevertheless, designers need to choose simulation models with appropriate fidelities to obtain qualities of interest (QOIs) at affordable cost levels. Generally, high-fidelity (HF) simulation models can provide more reliable and accurate simulation results than low-fidelity (LF) models. Consider the example of designing an airfoil, which is an aerodynamic component, the available simulation models for obtaining aerodynamic coefficients may differ in terms of their resolutions (e.g. coarse meshes versus refined meshes in finite element models), levels of abstraction (e.g. two-dimensional models versus three-dimensional models) or mathematical descriptions (e.g. the Euler non-cohesive equations versus the Navier–Stokes viscous Newton equations). Relying entirely on HF models to obtain QOIs for constructing a surrogate model is always time-consuming and may even be computationally prohibitive. On the other hand, LF models are considerably less computationally demanding. However, the QOIs obtained from LF models may result in inaccurate surrogate models or even distorted ones.