title: Size measurement of bubbles in a cavitation tunnel by digital in-line holography.
abstract: Digital in-line holography (DIH) with a divergent beam is used to measure size and concentration of cavitation bubbles (6-100 μm) in hydrodynamic facilities. A sampling probe is directly inserted in the cavitation tunnel, and the holograms of the bubbles are recorded through a transparent test section specially designed for DIH measurements. The recording beam coming from a fiber-coupled laser diode illuminates the sample volume, and holograms are recorded by a CMOS camera. From each hologram, the sampling volume can be reconstructed slice by slice by applying a wavelet-based reconstruction method. Because of the geometry of the recording beam, a magnification ratio must be introduced for recovering the 3D location and size of each bubble. The method used for processing holograms recorded in such a configuration is presented. Then, statistical results obtained from 5000 holograms recorded under different pressures in the cavitation tunnel are compared and discussed.
authors.affiliation: UMR 6614 CORIA, Université de Rouen, Avenue de l’Université, 76801 Saint-Etienne du Rouvray, France. denis.lebrun@coria.fr
authors.forename: Denis
authors.initials: D
authors.lastname: Lebrun
authors.forename: Daniel
authors.initials: D
authors.lastname: Allano
authors.forename: Loïc
authors.initials: L
authors.lastname: Méès
authors.forename: Françoise
authors.initials: F
authors.lastname: Walle
authors.forename: Frédéric
authors.initials: F
authors.lastname: Corbin
authors.forename: Romuald
authors.initials: R
authors.lastname: Boucheron
authors.forename: Didier
authors.initials: D
authors.lastname: Fréchou