Flow imaging as an alternative to pressure transducers through vision transformers and convolutional neural networks

TL;DR

This paper introduces a vision transformer-based framework for flow imaging that predicts pressure distributions and performs semantic segmentation, offering a promising alternative to traditional pressure sensors in fluid dynamics experiments.

Contribution

It develops a ViT model for pressure prediction from flow images and treats semantic segmentation as an image translation task, advancing flow visualization and surrogate modeling techniques.

Findings

ViT effectively predicts pressure distributions across flow regimes.

Semantic segmentation as image translation accurately identifies flow structures.

Models interpolate and extrapolate between different flow conditions.

Abstract

In this work, we propose a framework whereby flow imaging data is leveraged to extract relevant information from flowfield visualizations. To this end, a vision transformer (ViT) model is developed to predict the unsteady pressure distribution over an airfoil under dynamic stall from images of the flowfield. The network is capable of identifying relevant flow features present in the images and associate them to the airfoil response. Results demonstrate that the model is effective in interpolating and extrapolating between flow regimes and for different airfoil motions, meaning that ViT-based models may offer a promising alternative for sensors in experimental campaigns and for building robust surrogate models of complex unsteady flows. In addition, we uniquely treat the image semantic segmentation as an image-to-image translation task that infers semantic labels of structures from the input images in a supervised way. Given an input image of the velocity field, the resulting convolutional neural network (CNN) generates synthetic images of any corresponding fluid property of interest. In particular, we convert the velocity field data into pressure in order to subsequently estimate the pressure distribution over the airfoil in a robust manner.