Two-dimensional flow field measurement of sediment-laden flow based on ultrasound image velocimetry

TL;DR

This paper introduces a novel ultrasonic PIV technique using optical flow to measure instantaneous 2D velocity fields in sediment-laden flows, demonstrating improved accuracy and applicability over traditional methods.

Contribution

The paper develops an ultrasonic PIV system combining ultrasound imaging with optical flow, providing a new approach for sediment-laden flow measurement with enhanced accuracy and smoothness.

Findings

Accurately measures underwater velocity fields in sediment-laden flows.

Outperforms conventional cross-correlation algorithms in accuracy and smoothness.

Proves suitability for complex sediment-laden flow environments.

Abstract

This paper proposes a novel particle image velocimetry (PIV) technique to generate an instantaneous two-dimensional velocity field for sediment-laden fluid based on the optical flow algorithm of ultrasound imaging. In this paper, an ultrasonic PIV (UPIV) system is constructed by integrating a medical ultrasound instrument and an ultrasonic particle image velocimetry algorithm. The medical ultrasound instrument with a phased sensor array is used to acquire acoustic echo signals and generate two-dimensional underwater ultrasound images. Based on the optical flow field, the instantaneous velocity of the particles in water corresponding to the pixels in the ultrasonic particle images is derived from the grayscale change between adjacent images under the L-K local constraint, and finally, the two-dimensional flow field is obtained. Through multiple sets of experiments, the proposed algorithm is verified. The experimental results are compared with those of the conventional cross-correlation algorithms. The results show that the L-K optical flow method can not only obtain the underwater velocity field accurately but also has the advantages of good smoothness and extensive suitability, especially for the flow field measurement in sediment-laden fluid than conventional algorithms.