Modeling Continuous Spatial-temporal Dynamics of Turbulent Flow with Test-time Refinement

TL;DR

This paper introduces a novel flow reconstruction method that uses physical knowledge and test-time refinement to accurately generate high-resolution turbulent flow data from lower-resolution LES data, overcoming limitations of traditional super-resolution techniques.

Contribution

The proposed approach uniquely employs LES data only during testing with a degradation-based refinement to enforce physical constraints and improve reconstruction accuracy.

Findings

Effective in reconstructing high-resolution DNS data from LES inputs

Preserves physical attributes of turbulent flows during reconstruction

Achieves accurate DNS reconstruction across different resolutions

Abstract

The precise simulation of turbulent flows holds immense significance across various scientific and engineering domains, including climate science, freshwater science, and energy-efficient manufacturing. Within the realm of simulating turbulent flows, large eddy simulation (LES) has emerged as a prevalent alternative to direct numerical simulation (DNS), offering computational efficiency. However, LES cannot accurately capture the full spectrum of turbulent transport scales and is present only at a lower spatial resolution. Reconstructing high-fidelity DNS data from the lower-resolution LES data is essential for numerous applications, but it poses significant challenges to existing super-resolution techniques, primarily due to the complex spatio-temporal nature of turbulent flows. This paper proposes a novel flow reconstruction approach that leverages physical knowledge to model flow dynamics. Different from traditional super-resolution techniques, the proposed approach uses LES data only in the testing phase through a degradation-based refinement approach to enforce physical constraints and mitigate cumulative reconstruction errors over time. Furthermore, a feature sampling strategy is developed to enable flow data reconstruction across different resolutions. The results on two distinct sets of turbulent flow data indicate the effectiveness of the proposed method in reconstructing high-resolution DNS data, preserving the inherent physical attributes of flow transport, and achieving DNS reconstruction at different resolutions.