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arXiv · 2412.07456

Automatic extraction of wall streamlines from oil-flow visualizations using a convolutional neural network

Jonas Schulte-Sasse·Ben Steinfurth·Julien Weiss
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Abstract

Oil-flow visualizations represent a simple means to reveal time-averaged wall streamline patterns. Yet, the evaluation of such images can be a time-consuming process and is subjective to human perception. In this study, we present a fast and robust method to obtain quantitative insight based on qualitative oil-flow visualizations. Using a convolutional neural network, the local flow direction is predicted based on the oil-flow texture. This was achieved with supervised training based on an extensive dataset involving approximately one million image patches that cover variations of the flow direction, the wall shear-stress magnitude and the oil-flow mixture. For a test dataset that is distinct from the training data, the mean prediction error of the flow direction is as low as three degrees. A reliable performance is also noted when the model is applied to oil-flow visualizations from the literature, demonstrating the generalizability required for an application in diverse flow configurations.

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Jonas Schulte-Sasse, Ben Steinfurth, Julien Weiss. 2024-12-10. Automatic extraction of wall streamlines from oil-flow visualizations using a convolutional neural network. https://doi.org/10.1007/s00348-025-04016-x

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