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Hydrodynamic models are generally applied to describe the dynamic wetting of newtonian or non-newtonian fluids on a solid surface. Conversely, the molecular-kinetic paradigm is only utilized for spreading newtonian fluids while considering the movement of a contact line as a molecular hopping process. This study extended the molecular-kinetic paradigm to the wetting behavior of non-newtonian fluids, while assuming there are n fluid components at the contact line regime interacting simultaneously with a solid surface during front movement. The limiting cases of the derived model at slow and fast moving speeds were discussed. Moreover, the derived model was validated based on dynamic contact angle data of three carboxymethylcellulose (CMC) aqueous solutions measured using the force-balance method. Best-fit parameters were used to interpret the wetting dynamics of CMC solutions.
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http://dx.doi.org/10.1021/la102041q | DOI Listing |
Bioresour Technol
September 2025
College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China. Electronic address:
Docosahexaenoic acid (DHA) production via aerobic fermentation of Schizochytrium sp. is a green strategy, and the fermentation broth is a highly viscous, non-Newtonian fluid. In this study, the mixing and mass transfer of non-Newtonian fluids were enhanced using computational fluid dynamics combined with particle image velocimetry.
View Article and Find Full Text PDFBiorheology
September 2025
Department of Biomedical Engineering, University of Cincinnati, Veterans Affairs Medical Center, Cincinnati, OH, USA.
BackgroundThe viscosity of (BAF) influences the hemodynamics during testing of medical devices and implants in cardiovascular systems mimicking physiologic flow conditions. BAF, typically composed of water, glycerin, and Xanthan gum, is used to simulate blood's non-Newtonian shear-thinning behavior. Additionally, BAF may include microsphere particles for flow visualization in Laser Doppler Velocimetry (LDV) experiments, though their impact on viscosity remained an under-investigated area.
View Article and Find Full Text PDFSoft Matter
September 2025
School of Civil Engineering, The University of Sydney, 2006 NSW, Australia.
Objects moving through granular materials experience a drag force. In the past two decades, many studies have revealed its non-trivial properties, including dependencies on the velocity of the object and the pressure around it. This tutorial review introduces some of these properties and their associated scaling laws.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
Microfluidics and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati-781039, Assam, India.
We numerically investigate the mixing characteristics of non-Newtonian fluids under the ion-partitioning effect in a micromixer having a built-in patterned soft polyelectrolyte layer (PEL) on its inner wall surfaces. We show that the mixing phenomenon is greatly modulated by the migration of counter-ions triggered by the Born energy difference caused by the electrical permittivity differences between the PEL and bulk electrolyte. We demonstrate counter-ion concentration field, flow velocity variation, species concentration distribution, mixing efficiency and neutral species dispersion by varying the electrical permittivity ratio and rheological parameters.
View Article and Find Full Text PDFSci Rep
September 2025
Department of Mechanical Engineering, College of Engineering, University of Ha'il, Ha'il City, 81451, Saudi Arabia.
Accurate assessment of intracranial aneurysm rupture risk, particularly in Middle Cerebral Artery (MCA) aneurysms, relies on a detailed understanding of patient-specific hemodynamic behavior. In this study, we present an integrated framework that combines Computational Fluid Dynamics (CFD) with Proper Orthogonal Decomposition (POD) and machine learning (ML) to efficiently model pulsatile blood flow using a Casson non-Newtonian fluid model, without incorporating fluid-structure interaction (FSI). Patient-specific vascular geometries were reconstructed from DICOM imaging data and simulated using ANSYS Fluent to capture key hemodynamic factors, including velocity components, pressure, wall shear stress (WSS), and oscillatory shear index (OSI).
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