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Control of viscoplastic fluid dynamics in superhydrophobic channels with asymmetric groove configurations
DOI:10.1016/j.jnnfm.2025.105420.png)
Abstract
En 中文
We study the plane Poiseuille flow of viscoplastic fluids in channels with asymmetric superhydrophobic (SH) walls featuring transverse groove configurations in the thin channel limit. We use OpenFOAM simulations and the Papanastasiou regularization method to approximate the Bingham model. Focusing on variations in the upper SH wall's characteristics, we explore the effects of slip number (b2), groove periodicity length (82), slip area fraction (P2), and Bingham number (B) on flow dynamics, flow metrics and unyielded center plug morphology. We find that increasing b2, P2, and 82 enhances slip velocity on the upper SH wall and reduces the normalized plug area (A/A0) up to P2 = 0.5, while higher B amplifies flow asymmetry, shifting and breaking center plugs. By introducing the concept of slippery equivalent systems, we demonstrate that varying groove configurations can yield identical effective slip lengths (xT) with distinct plug morphologies, enabling precise control of viscoplastic fluid dynamics. We derive a simplified model to predict xT and A/A0, identifying a critical threshold at A/A0 approximate to 0.68 for regime transitions between unbroken (Regime I) and broken (Regime II) center plugs, leading to a six-dimensional manifold equation for classifying these regimes across parameter space.
Keywords:
Viscoplastic fluids
Superhydrophobic surfaces
Effective slip length
Yield stress fluids
Numerical simulations
Journal
J
IF:
2.8
Papers:
153
Citations:
7.6K

