Modeling Droplet Impingement Dynamics on Micropillar-Arrayed Viscoelastic Substrates Through Microgeometry-Free and Multiscale Methods

The droplet impact dynamics on micropillar-arrayed viscoelastic substrates has been thoroughly investigated by two distinct modeling methods, i.e., microgeometry-free and multiscale modeling methods. The viscoelasticity of the micropillar-arrayed substrate is characterized by a five-parameter generalized Maxwell model via the Laplace-Carson transform. In the microgeometry-free modeling, only one general domain containing all the modeled objects is constructed with the detailed geometry of micropillars omitted. In contrast, by multiscale modeling, two different geometric-scale domains are employed to investigate the deformation of individual micropillars in the smaller domain named zoomed-in domain and the effects of the deducted deformation velocity on the fluid field evolution in the larger domain called the zoomed-out domain. These two methods both have advantages and disadvantages regarding efficiency, accuracy and information completeness and emphasis. The microgeometry-free method serves as an efficient tool to rapidly determine the flow evolution after droplet impingement, while being deficient to accurately describe the individual micropillar deformation. By contrast, the multiscale method can appropriately stress this issue by constructing magnification domains along the bottom micropillar array with the entrapped gas cushioning effect evaluated, which in turn results in a more precise illustration of fluid field evolution. However, due to more details considered, this method becomes much more time consuming and requires significant computational resources. Although the microgeometry-free and multiscale modeling methods are implemented via distinct procedures, they share some common aspects such as using the general larger domain to define the macroscopic flow evolution and leveraging the generalized Maxwell model to characterize substrate viscoelasticity. This indicates that these two methods are interrelated rather than independent. Therefore, they together substantially demonstrate the evolution of droplet and the deformation of micropillar array, and significantly provide meaningful clues to understand fluid-structure interaction with enormous geometric-scale inconsistency and complex physical properties involved.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2026

Author dc:creator

• Li, Yang

Chair dc:contributor.committeechair

• Cheng, Jiangtao

Committee members dc:contributor.committeemember

• Paul, Mark R.
• Yue, Pengtao
• Liu, Yang

• droplet impingement
• micropillar-arrayed viscoelastic substrate
• droplet-gas two-phase flow
• multiscale modeling

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:45540

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/141059