PIV adaptive interrogation and sampling with image projection applied to water sloshing

Abstract

The measurement of fluid velocity in the vicinity of wavy interfaces by means of Particle Image Velocimetry (PIV) still constitutes a challenge. Besides the experimental complexities such as appropriate seeding, reflections due to gradients in refractive indices, aberrations, etc., also the image processing phase constitutes a critical component. Ignoring bias errors introduced by laser reflections near the interface, strong velocity gradients are typically encountered near the curved liquid/gas interface and are detrimental to the common cross-correlation analysis. These effects are exacerbated by the use of traditional rectangular static cross-correlation windows. More-

Simultaneous interface position and bulk velocity measurements in cryogenic sloshing

“…Nevertheless, due to the location of the convective motions in the bottom part of the cell, it can be assumed that they will not influence the liquid velocities close to the liquid/gas interface. At the steady state the velocity profiles along the liquid height at the radial location x = −0.5 Rtank have been computed and show as predicted in the literature an exponential decay [26,27]. This analysis, can be considered as a further prove of the technique feasibility.…”

Proper orthogonal decomposition, dynamic mode decomposition, wavelet and cross wavelet analysis of a sloshing flow

“…In terms of experimental characterization of sloshing flows, activities during 1960's NASA space programs focused on the determination of equivalent mechanical model parameters via system identification techniques, complemented with photographic images of the generally linear sloshing flow regimes (Abramson, 1966). More recently non-intrusive measurements such as PIV (Particle Image Velocimetry) have been employed successfully to measure the velocity field and track the free surface (Simonini et al, 2014(Simonini et al, , 2015(Simonini et al, , 2016. Owing to its importance for Liquid Natural Gas (LNG) tanker design, the measurement of unsteady pressures due to wave impacts have been the focus of intense research, see amongst others (Delorme et al, 2009;Brosset et al, 2009;Ibrahim, 2020).…”

Free surface reconstruction of opaque liquids in microgravity, Part 1: Design and on-ground testing

“…Alternatively, the distortion of a pattern behind the liquid can be employed [22,23], an approach that has been addressed with deep neural networks in modern works [24]. Particle image velocimetry makes use of the motion of seeding particles in the fluid [25,26]. In stereo imaging, the liquid surface and underwater scene are recorded by an array of cameras and then reconstructed [27].…”