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

A. Simonini*, Raf Theunissen, A. Masullo, M. R. Vetrano

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

5 Citations (Scopus)

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. Moreover, dynamic boundaries suffer from a certain loss in reliability due to the difference in number of particles located in a specific physical region between the two frames. In this paper we present an improved algorithm enhancing the accuracy of the velocity vector detection in dynamic wavy flows. This algorithm divides the fluid domain in subregions (i.e. bulk, intermediate, vicinity and interface) and applies to each region different features (such as image patching, window relocation and forward difference finite schemes) and ad hoc predictors. Its assessment is performed on the basis of synthetic images, which reproduce a wavy motion similar to the one encountered when fluid in a cylindrical reservoir undergoes sloshing. When juxtaposed with a standard PIV code, numerical errors are shown to strongly diminish while improving the spatial resolution approaching the interface. The algorithm is finally applied to experimental PIV images of water sloshing in a cylindrical reservoir to provide more reliable results at the interface, contrary to standard PIV codes.

Original languageEnglish
Pages (from-to)559-574
Number of pages16
JournalExperimental Thermal and Fluid Science
Volume102
Early online date13 Dec 2018
DOIs
Publication statusPublished - 1 Apr 2019

Keywords

  • Adaptive PIV
  • Dynamic interfaces
  • Free surface flows
  • Sloshing

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