On the (in)equality of droplet rebound dynamics at fixed Weber number

Berce, Jure (avtor), Golobič, Iztok (avtor)

The similarity of droplet impacts on nature-mimicking superhydrophobic surfaces is traditionally compared using the dimensionless Weber number. Yet, maintaining a constant We by decoupling droplet diameter and impact velocity influences secondary forces, challenging this assumption of similarity. In this work, we investigate water droplet impacts on a lotus-leaf-mimicking laser-textured superhydrophobic aluminum surface at two constant Weber number levels (25 and 50), varying droplet diameter from 2.1 to 4.15 mm. Our results confirm that maximum spreading depends on the Reynolds number at a fixed We, as smaller, faster droplets spread less due to increased relative viscous dissipation. We propose a modified empirical scaling model that describes our data with high accuracy and generalizes successfully to external datasets. Crucially, we demonstrate that the contact time of a droplet of a given size is not strictly velocity-independent, unveiling a Weber number-dependent inertia-capillary scaling. We show that this is driven by a shift in rebound dynamics, where the relative timescale of spreading increases over retraction for larger droplets. These findings demonstrate that We is insufficient to characterize droplet rebound across varying scales and that accounting for size-dependent deviations is critical for the precise design of technologies that leverage droplet-surface interactions.

• Jezik: Angleški jezik
• Ključne besede: droplet rebound, superhydrophobic surface, Weber number, rebound dynamics, maximum spreading coefficient, contact time
• 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: 15 str.
• Številčenje: Vol. 11, iss. 9, art. 640
• PID: 20.500.12556/RUL-186914
• UDK: 532.21:544.722.132
• ISSN pri članku: 2313-7673
• DOI: 10.3390/biomimetics11090640
• COBISS.SI-ID: 290161411
• Datum objave v RUL: 07.09.2026

Gradivo je del revije

• Naslov: Biomimetics
• Skrajšan naslov: Biomimetics
• Založnik: MDPI
• ISSN: 2313-7673
• COBISS.SI-ID: 526328601

Licence

• Licenca: CC BY 4.0, Creative Commons Priznanje avtorstva 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by/4.0/deed.sl
• Opis: To je standardna licenca Creative Commons, ki daje uporabnikom največ možnosti za nadaljnjo uporabo dela, pri čemer morajo navesti avtorja.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: odboj kapljice, superhidrofobne površine, Webrovo število, dinamika odboja, maksimalni koeficient širjenja, kontaktni čas

Projekti

• Financer: ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
• Številka projekta: P2-0223
• Naslov: Prenos toplote in snovi

• Financer: ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
• Številka projekta: J2-50085
• Naslov: Raziskave medfaznih pojavov kapljic in mehurčkov na funkcionaliziranih površinah ob uporabi napredne diagnostike za razvoj okoljskih tehnologij prihodnosti in izboljšanega prenosa toplote (DroBFuSE)