Direct observation of shockwaves, cavitation, and jetting inside liquid droplets during high-speed impact

Agrež, Vid (avtor), Gonzalez-Avila, Silvestre Roberto (avtor), Horvat, Darja (avtor), Xie, Run-Ze (avtor), Zeng, Qingyun (avtor), Petkovšek, Rok (avtor), Ohl, Claus-Dieter (avtor)

This study reports direct experimental observations of shockwave propagation and cavitation bubble formation inside liquid water droplets during high-speed impact (80 –180 m/s) on solid surfaces, together with jetting observed at the distal end of the droplet. Ultra-high-speed shadowgraph and angle-view imaging at 10 million frames per second resolved two distinct internal wave structures: a primary compression front (1500–2050 m/s), consistent with pressure-dependent corrections to the acoustic wave speed, and a secondary tension wave emerging approximately 500 ns later, generated by reflection at the curved water–air interface. The curved distal surface focuses converging rarefaction waves into a caustic region, leading to cavitation nucleation 1.2–1.5 µs after impact. The subsequent asymmetric collapse of these cavitation structures drives directed jetting from the distal end, with jet morphology dependent on droplet geometry: coherent jets for smaller spherical droplets (<2 mm) whereas spray-like ejection is typical for larger, elongated droplets (>2 mm). At the proximal end of the droplet, air is entrapped between the surface and the droplet, collapsing into a toroidal-shaped bubble that exhibits oscillations in the 0.5–1.8 MHz range. All presented results, including experimental data and accompanying analysis, provide benchmark validation data for computational models of compressible droplet impact.

• Jezik: Angleški jezik
• Ključne besede: cavitation, droplet impact, shockwaves, acoustic focusing, high-speed imaging
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FS - Fakulteta za strojništvo
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2026
• Št. strani: Str. 1-13
• Številčenje: Vol. 134, art. 108121
• PID: 20.500.12556/RUL-190890
• UDK: 532.528:004.932
• ISSN pri članku: 1873-2828
• DOI: 10.1016/j.ultsonch.2026.108121
• COBISS.SI-ID: 304216579
• Datum objave v RUL: 06.11.2026

Gradivo je del revije

• Naslov: Ultrasonics Sonochemistry
• Založnik: Elsevier
• ISSN: 1873-2828
• COBISS.SI-ID: 23127813

Licence

• Licenca: CC BY-NC 4.0, Creative Commons Priznanje avtorstva-Nekomercialno 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by-nc/4.0/deed.sl
• Opis: Licenca Creative Commons, ki prepoveduje komercialno uporabo, vendar uporabniki ne rabijo upravljati materialnih avtorskih pravic na izpeljanih delih z enako licenco.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: kavitacija, trk kapljice, udarni valovi, akustično fokusiranje, visokohitrostno slikanje

Projekti

• Financer: ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
• Številka projekta: P2-0270-2022
• Naslov: Proizvodni sistemi, laserske tehnologije in spajanje materialov

• Financer: Drugi - Drug financer ali več financerjev
• Program financ.: Deutsche Forschungsgemeinschaft
• Številka projekta: OH 75/12-1
• Naslov: /