Spatiotemporal analysis of transient liquid film shape

Vidic, Gašper (author), Bajt, Saša (author), Šarler, Božidar (author)

Precise control of thin liquid film deposition is crucial in applications where film stability and internal liquid flow significantly impact the dry film shape or the efficiency of sample or drug delivery. No prior work has automated the extraction and measurement uncertainty quantification of film geometric parameters from dual-view optical visualization with minimal user input. We present Python-based software that extracts time-resolved film thickness, width, and the positions of three contact lines from visual data using computer vision. The utility of such analysis is demonstrated by depositing 30 % glycerol on a flexible tape through a circular nozzle orifice. The nozzle is positioned at a distance of h = 0.3 mm from the tape at an angle of attack α = 45°, with deposition controlled at a volume flow rate ▫$\dot{V}$▫ = 30 μL ▫$min^{−1}$▫ and tape velocity v = 1.0 mm ▫$s^{−1}$▫. Expanded measurement uncertainties are 21 μm, 22 μm, and 53 μm for the upstream static, downstream static, and upstream dynamic contact line positions, respectively, with maximum relative uncertainties of 10.3 % and 8.2 % for film thickness and width. Static contact line oscillations remain within measurement uncertainty, whereas the upstream dynamic contact line exhibits resolvable oscillations. This dual-view framework provides high-resolution insights into liquid film dynamics, which is crucial for comprehensive control of liquid film deposition.

• Language: English
• Keywords: liquid film shapes, dual-view imaging, optical visualization, automated spatiotemporal analysis
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 19 str.
• Numbering: Vol. 11, issue 3, art. 67
• PID: 20.500.12556/RUL-180157
• UDC: 532.5:544.023
• ISSN on article: 2311-5521
• DOI: 10.3390/fluids11030067
• COBISS.SI-ID: 270390531
• Publication date in RUL: 04.03.2026

Record is a part of a journal

• Title: Fluids
• Shortened title: Fluids
• Publisher: MDPI AG
• ISSN: 2311-5521
• COBISS.SI-ID: 525935385

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: oblike kapljevinskega sloja, zajem slik iz dveh pogledov, optična vizualizacija, avtomatizirana prostorsko-časovna analiza