boxuez

• Zheng, Boxue; Chan, Tak Shing; Brummelen, Harald Van & Snoeijer, Jacco H. (2025). Dynamics of poro-viscoelastic wetting with large swelling. Journal of Fluid Mechanics. ISSN 0022-1120. 1025(A58). doi: 10.1017/jfm.2025.10977. Full text in Research Archive Show summary

  The deposition of droplets onto a swollen polymer network induces the formation of a wetting ridge at the contact line. Current models typically consider either viscoelastic effects or poroelastic effects, while polymeric gels often exhibit both properties. In this study, we investigate the growth of the wetting ridge using a comprehensive large-deformation theory that integrates both dissipative mechanisms – viscoelasticity and poroelasticity. In the purely poroelastic case, following an initial instantaneous incompressible deformation, the growth dynamics exhibits scale-free behaviour, independent of the elastocapillary length or system size. A boundary layer of solvent imbibition between the solid surface (in contact with the reservoir) and the region of minimal chemical potential is created. At later times, the ridge equilibrates on the diffusion time scale given by the elastocapillary length. When viscoelastic properties are incorporated, our findings show that, during the early stages (prior to the viscoelastic relaxation time scale), viscoelastic effects dominate the growth dynamics of the ridge and solvent transport is significantly suppressed. Beyond the relaxation time, the late-time dynamics closely resembles that of the purely poroelastic case. These findings are discussed in light of recent experiments, showing how our approach offers a new interpretation framework for wetting of polymer networks of increasing complexity.

• Zheng, Boxue & Chan, Tak Shing (2025). Soft Wetting Ridge Rotation in Sessile Droplets and Capillary Bridges. Langmuir. ISSN 0743-7463. 41(6). doi: 10.1021/acs.langmuir.4c04667. Full text in Research Archive Show summary

  We investigate the deformation of soft solid layers in the presence of sessile droplets or capillary bridges. Unlike models that assume Young’s law governs the contact angle, we incorporate the surface tension balance at the contact line to analyze the rotation of the wetting ridge and the corresponding change in the contact angle. Our findings reveal that the rotation direction of the wetting ridge aligns with the sign of the Laplace pressure. Interestingly, although a softer solid layer typically decreases the contact angle for sessile droplets, a negative Laplace pressure in a hydrophilic capillary bridge pulls the solid–liquid interface, leading to an increased contact angle. A hydrophilic capillary bridge would be expected to move from thicker regions of a soft layer to thinner areas, exhibiting behavior opposite that of a sessile droplet. The interplay between soft layer deformation and contact angle modulation provides valuable insights into controlling droplet motion through elastocapillarity.

• Zheng, Boxue; cai, zhiwen; zhao, peidong; xu, xiaoyang; Chan, Tak Shing & peng, yu (2024). A generalized density dissipation for weakly compressible smoothed particle hydrodynamics. Physics of Fluids. ISSN 1070-6631. 36(8). doi: 10.1063/5.0216702. Full text in Research Archive Show summary

  Weakly compressible smoothed particle hydrodynamics (SPH) is known to suffer from numerical pressure noise, posing challenges to simulation stability and accuracy. To address this, the present study introduces a novel density dissipation scheme aimed at suppressing such unphysical noise. The proposed solution overcomes the limitation of traditional density dissipation schemes being ineffective at fluid interfaces in multiphase flow simulations. The novel scheme is generally applicable to the entire computational domain, encompassing both single-phase flow and multiphase flow. This advancement is achieved through two key components. First, the traditional density dissipation is replaced with a density increment dissipation approach that enables dissipation to cross interfaces separating different fluids. Second, based on dissipation volume conservation, a dissipation volume correction factor is employed to stabilize simulations characterized by large density ratios. The accuracy, stability, and robustness of our method are demonstrated through direct comparisons with experimental data or numerical results in four three-dimensional benchmarks: sloshing under external excitations, the rising of single and double bubbles, Rayleigh–Taylor instability, and Kelvin–Helmholtz instability. Additionally, our study reveals the relationship between SPH utilizing density dissipation and the approximate Riemann solver.

• Zheng, Boxue; Pedersen, Christian; Carlson, Andreas & Chan, Tak Shing (2023). Static wetting of a barrel-shaped droplet on a soft-layer-coated fiber. Soft Matter. ISSN 1744-683X. 19(46), p. 8988–8996. doi: 10.1039/d3sm00951c. Full text in Research Archive Show summary

  A droplet can deform a soft substrate due to capillary forces when they are in contact. We study the static deformation of a soft solid layer coated on a rigid cylindrical fiber when an axisymmetric barrel-shaped droplet is embracing it. We found that elastic deformation increases with a decreasing rigid fiber radius. Significant disparities of deformation between the solid–liquid side and the solid–gas side are found when their solid surface tensions are different. When the coated layer is soft enough and the rigid fiber radius is less than the thickness of the coated layer, pronounced displacement oscillations are observed. Such slow decay of deformation with distances from the contact line position suggests a possible long-range interaction between droplets on a soft-layer-coated fiber.

• Zheng, Boxue; Sun, Lei; Chen, Zhen; Cheng, Cong & Liu, Changfeng (2021). Multiphase smoothed particle hydrodynamics modeling of forced liquid sloshing. International Journal for Numerical Methods in Fluids. ISSN 0271-2091. 93(2), p. 411–428. doi: 10.1002/fld.4889. Full text in Research Archive
• Zheng, Boxue; Sun, Lei & Yu, Peng (2021). A novel interface method for two-dimensional multiphase SPH: Interface detection and surface tension formulation. Journal of Computational Physics. ISSN 0021-9991. 431. doi: 10.1016/j.jcp.2021.110119. Full text in Research Archive
• Zheng, Boxue & Chen, Zhen (2019). A multiphase smoothed particle hydrodynamics model with lower numerical diffusion. Journal of Computational Physics. ISSN 0021-9991. 382, p. 177–201. doi: 10.1016/j.jcp.2019.01.012. Full text in Research Archive

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• Zheng, Boxue; Chan, Tak Shing; Brummelen, Harald van & Snoeijer, Jacco H. (2024). Title Capillary-Induced Deformation and Solvent Transport in Hydrogels. Full text in Research Archive
• Zheng, Boxue; Chan, Tak Shing; Brummelen, Harald van & Snoeijer, Jacco H. (2024). Capillary-Induced Deformation and Solvent Transport in Hydrogels. Full text in Research Archive
• Zheng, Boxue; Pedersen, Christian; Carlson, Andreas & Chan, Tak Shing (2023). Static wetting of a droplet on a soft-layer-coated fiber. Full text in Research Archive
• Zheng, Boxue; Pedersen, Christian; Carlson, Andreas & Chan, Tak Shing (2023). Static wetting of a droplet on a soft-layer-coated fiber. Full text in Research Archive
• Zheng, Boxue; Pedersen, Christian; Carlson, Andreas & Chan, Tak Shing (2023). Static wetting of a barrel-shaped droplet on a soft-layer-coated fiber. Full text in Research Archive
• Chan, Tak Shing & Zheng, Boxue (2023). Capillary bridges between partially wetting soft substrates. Full text in Research Archive
• Zheng, Boxue; Pedersen, Christian; Carlson, Andreas & Chan, Tak Shing (2023). Static wetting of a droplet embracing a fiber coated with a soft layer. Full text in Research Archive

View all works in NVA