internal structure and the effect of non-axisymmetric boundary conditions
Juan Manuel Rosselló (Author), Hannes Paul Hoeppe (Author), Max Koch (Author), Christiane Lechner (Author), Markus Osterhoff (Author), Malte Vassholz (Author), Johannes Hagemann (Author), Johannes Möller (Author), Markus Scholz (Author), Ulrike Boesenberg (Author)

Abstract

In this work, we study the jetting dynamics of individual cavitation bubbles using x-ray holographic imaging and high-speed optical shadowgraphy. The bubbles are induced by a focused infrared laser pulse in water near the surface of a flat, circular glass plate, and later probed with ultrashort x-ray pulses produced by an x-ray free-electron laser (XFEL). The holographic imaging can reveal essential information of the bubble interior that would otherwise not be accessible in the optical regime due to obscuration or diffraction. The influence of asymmetric boundary conditions on the jet’s characteristics is analysed for cases where the axial symmetry is perturbed and curved liquid filaments can form inside the cavity. The x-ray images demonstrate that when oblique jets impact the rigid boundary, they produce a non-axisymmetric splash which grows from a moving stagnation point. Additionally, the images reveal the formation of complex gas/liquid structures inside the jetting bubbles that are invisible to standard optical microscopy. The experimental results are analysed with the assistance of full three-dimensional numerical simulations of the Navier–Stokes equations in their compressible formulation, which allow a deeper understanding of the distinctive features observed in the x-ray holographic images. In particular, the effects of varying the dimensionless stand-off distances measured from the initial bubble location to the surface of the solid plate and also to its nearest edge are addressed using both experiments and simulations. A relation between the jet tilting angle and the dimensionless bubble position asymmetry is derived. The present study provides new insights into bubble jetting and demonstrates the potential of x-ray holography for future investigations in this field.

Keywords

rentgenska holografija;brizganje mehurčkov;simulacije OpenFOAM;x-ray holography;bubble jetting;OpenFOAM simulations;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL FS - Faculty of Mechanical Engineering
UDC: 532.528:004.94
COBISS: 183556099 Link will open in a new window
ISSN: 0723-4864
Views: 19
Downloads: 3
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Other data

Secondary language: Slovenian
Secondary keywords: rentgenska holografija;brizganje mehurčkov;simulacije OpenFOAM;
Type (COBISS): Article
Pages: str. 1-26
Issue: ǂVol. ǂ65, article no. 20
Chronology: Feb. 2024
DOI: 10.1007/s00348-023-03759-9
ID: 23649481