Visualization and analysis of jet oscillation under transverse acoustic perturbation

TL;DR

This paper presents two image processing methods to analyze jet oscillations under acoustic perturbation, validating their effectiveness on simulated and real jets, and exploring factors affecting jet behavior.

Contribution

Introduction of two complementary image analysis techniques for studying jet oscillations under acoustic perturbation, validated on synthetic and real data.

Findings

Both methods produce consistent results, confirming their reliability.

The methods effectively estimate the convection velocity of perturbations.

Jet behavior varies with Reynolds number and upstream channel geometry.

Abstract

Schlieren flow visualizations of transverse oscillations of jets submitted to an acoustic perturbation are analyzed in this paper. The aim is to estimate the shape and the position of the median line of the jet. Two methods for image processing are proposed, based on complementary approaches : inter image and intra image analysis. Synthesized images of an oscillating jet are used to validate each method and compare their performances in the case of noisy pictures. Illustrations are then shown on real laminar and turbulent jets. The results obtained using both methods are very close, showing their reliability. Applications investigated in this paper are focused on the estimation of the convection velocity of perturbations along the jet, and the influence of the Reynolds number and of the channel geometry upstream the jet formation.