Article
Ecology
Pritam Kumar, Anurag Sharma
Summary: This study investigates the impact of emergent rigid vegetation on free surface flows. The presence of vegetation reduces flow velocity, Reynolds shear stress, and turbulence intensities, leading to a reduction in flow resistance.
Article
Mechanics
Julien Ferec, Erwan Bertevas, Boo Cheong Khoo, Gilles Ausias, Nhan Phan-Thien
Summary: The perturbation technique based on the retardation-motion expansion is commonly used to study flow solutions at low Weissenberg numbers, particularly in analyzing the motion of fibers suspended in viscoelastic fluids. The analysis reveals that fibers align along the vorticity direction under shear flow, with different orientations observed when considering various viscoelastic fluid models. Additionally, good agreement with experimental data is found in the conservation equation for particle concentration, indicating particle migration in a pressure-driven flow channel.
Article
Mechanics
Hyota Hozumi, Yuki Nohara, Yoshiki Horikawa, Toshiyuki Shikata
Summary: This study systematically investigated the dynamic viscoelastic properties of N-methylpyrrolidone (NMP) solutions of poly(vinylidene fluoride) (PVDF) samples with a wide range of weight average molar masses. It was found that the increase in activation energy is caused by the contact or entanglement of PVDF molecules.
JOURNAL OF RHEOLOGY
(2023)
Article
Energy & Fuels
Idrees Khan, Tiri Chinyoka, Andrew Gill
Summary: In this study, the shear banding phenomena and its impact on heat transfer in viscoelastic-fluid-based nanofluids were investigated. The results showed that the viscoelastic nanofluids exhibited lower susceptibility to thermal runaway and significant enhancement in heat transfer compared to conventional nanofluids under shear banding conditions.
Article
Mathematics
Mu-Jung Lee, Shih-Chun Hsiao
Summary: This study investigates the impact of currents on waves and derives a third-order analytical solution for bichromatic waves on non-uniform currents. Unlike previous research, this study proposes a method that can handle multiple waves with different velocities and consider the rotational nature of the flow. The findings are important for understanding the interaction between waves and currents.
Article
Mathematics, Interdisciplinary Applications
Catia Costa e Silva, Sascha Florian Maassen, Paulo M. Pimenta, Jorg Schroder
Summary: This work simultaneously uses geometrically exact shear-rigid rod and shell finite elements within the same framework. The rotation field is parameterized by Rodrigues rotation vector, simplifying the incremental updating of rotational variables. Internal and boundary incremental torsion angles are made compatible through an internal Lagrange multiplier.
COMPUTATIONAL MECHANICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Anfeng Hu, Senlin Xie, Zhirong Xiao, Xunjian Hu, Meihui Wang, Yuan Chen, Yiyang Chen
Summary: This paper presents a novel analytical solution for the consolidation behavior of viscoelastic saturated soft soil under large-scale ground loading. The study shows that the soil permeability coefficient, Newtonian viscosity coefficient, and Hooke's spring modulus have significant influences on the dissipation of excess pore water pressure and the degree of consolidation. The permeability condition of the tunnel also affects the distribution of excess pore water pressure in the soil layer above the tunnel.
COMPUTERS AND GEOTECHNICS
(2024)
Article
Mechanics
Ming Wang, Zhiyuan Yang, Peng Wu, Hai Fang, Ruili Huo
Summary: This study develops an analytical model to investigate the time-varying performance of multilayer functionally graded plates glued by viscoelastic interlayers. The stress and displacement solutions for the multilayer plate are analytically derived using series expansion and Laplace transformation. The results show that the stress and displacement distributions of the multilayer functionally graded plate can be optimized by changing the gradient index.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Engineering, Geological
Y. Y. Zhou, B. Yu, W. Fan, T. A. Dijkstra, Y. N. Wei, L. S. Deng
Summary: The study investigates the development of localized shear failure in Malan loess through laboratory triaxial shear test and X-ray micro-computed tomography. It is found that multiple undulating fracture surfaces gradually increase until a dominant shear failure plane is formed. The shear band of finite thickness has an increasing macroporosity. These findings provide important insights into the multi-scale modelling of loess mechanical behavior.
ENGINEERING GEOLOGY
(2023)
Article
Engineering, Marine
Julia Hopkins, Matthieu de Schipper, Meagan Wengrove, Bruno Castelle
Summary: Observations and simulations show the effect of wave-current interaction on shear stress around a sandy mound. The response of shear stress to the mound is nonlinear and influenced by the ratio of wave-current energy. The spatial distribution of shear stress becomes asymmetric with more mixed wave-current flows, impacting sediment transport and mound evolution.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Mechanics
Amir Arshadi, Mahdi Nili-Ahmadabadi, Ali Minaeian, Mahmood Norouzi, Man Yeong Ha
Summary: Flow and heat transfer of a viscoelastic fluid around a hot rotating cylinder in a square enclosure were numerically studied using the Phan-Thien-Tanner (PTT) model. The effects of the Weissenberg number, Brinkman number, Reynolds number, and the ratio of the polymeric viscosity to total viscosity on the behavior of fluid flow and heat transfer were investigated. Increasing the Weissenberg number led to a higher shear thinning effect, which increased heat transfer and decreased frictional torque applied to the cylinder.
Article
Chemistry, Physical
Cheng-Wei Tai, Vivek Narsimhan
Summary: This study experimentally verifies the cross-stream migration of particles in microfluidic systems and develops a mathematical model based on a second order fluid to predict the particle migration speed in real systems.
Article
Polymer Science
Ahmed Abusabir, Muhammad A. Khan, Muhammad Asif, Kamran A. Khan
Summary: This study investigates the effect of architected structural member geometry and base material on the viscoelastic response of 3D printed lattice structure. The results show that both material and topology influence the mechanical properties and time-dependent behavior of the lattice structure. Plate-based lattices are the best choice for creep resistance, while shell-based lattices are ideal for damping applications under quasi-static loading conditions.
Article
Materials Science, Multidisciplinary
Seyed Hashem Alavi, Hamidreza Eipakchi
Summary: Accurate understanding of the dynamic behavior of viscoelastic plates is crucial in designing and optimizing their mechanical/vibrational behavior. This study analytically determined the dynamic response of annular sector plates under asymmetric impulsive and harmonic transverse loads, considering different boundary conditions and theoretical models which have significant influence on the results.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2022)
Article
Computer Science, Interdisciplinary Applications
Svetlana Tlupova
Summary: A robust and highly accurate numerical solution framework is developed for the coupled Stokes-Darcy system in three dimensions. The method employs domain decomposition and iterative solving of separate Stokes and Darcy problems. Boundary integral equations are formulated and utilize smoothing of the kernels and direct quadrature for high accuracy on the boundary.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Mechanics
Arif Mahmud, Shaocong Dai, Roger Tanner
JOURNAL OF RHEOLOGY
(2020)
Article
Mechanics
Kostas D. Housiadas, Jeremy P. Binagia, Eric S. G. Shaqfeh
Summary: In this study, we investigated various aspects of the spherical squirmer model in weakly elastic fluids using large-scale numerical simulations and asymptotic methods. Our findings show that the low-Wi region plays a crucial role in enhancing speed and rotation rate in perturbation solutions.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Arif Mahmud, Shaocong Dai, Roger Tanner
Summary: The response of non-colloidal suspensions to sudden strains and sudden changes of strain rate was investigated using silicone oil and glycerol/water as matrix fluids. A Oldroyd-B model augmented by a friction element accurately described the shear stresses, with friction becoming dominant for volume fractions greater than 0.3.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2021)
Article
Mechanics
Kostas D. Housiadas
Summary: This study theoretically investigates an active, self-propelled, spherical microbody in a weakly viscoelastic matrix fluid using analytical techniques. Three dimensionless numbers arise from the elastic stress in the governing equations, and the impact of slip parameters on singularity in viscoelastic stress for different constitutive models is discussed. The effect of secondary slip and swirl parameters on swimming velocity enhancement, as well as the variety of swimming behaviors influenced by the secondary slip parameter, are emphasized.
Article
Mechanics
Roger I. Tanner
Summary: The paper suggests that a modified Oldroyd-B model can be utilized to describe the rheology of non-colloidal suspensions with a viscoelastic matrix. Professor R. Byron Bird had previously utilized Oldroyd models for around 50 years in studying rheological behavior.
Article
Mechanics
Roger Tanner, Shaocong Dai
Summary: An inelastic model of non-Brownian suspension behavior based on the persistence of straining concept of Thompson and Souza Mendes (TSM model) is proposed and compared with experiments and computations in various flow conditions. The model shows good agreement in general and highlights the significant influence of interparticle friction, which has been incorporated via a bootstrap concept.
Article
Mechanics
Spyros D. Gkormpatsis, Kostas D. Housiadas, Antony N. Beris
Summary: This study analytically investigates the effect of perfect slip boundary conditions on the steady translation of a spherical particle in a viscoelastic fluid. It is found that under perfect slip conditions, the relative drag force on the sphere increases monotonically with viscoelasticity.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2022)
Article
Mechanics
Roger I. Tanner, Shaocong Dai
Summary: This paper proposes a two-part composite model to describe the rheology of non-Brownian suspensions and demonstrates how to determine the parameters for agreement with experimental and computational results. Although the agreement with experiments and computations is reasonable, more accurate calculations and experiments would be desirable.
Article
Mechanics
Kostas D. Housiadas, Christos Tsangaris
Summary: Lubrication theory is extended to study the laminar flow of an incompressible and highly viscous simple Newtonian fluid in microfluidic channels and tubes with variable geometry. The analysis includes different shapes for the walls and axisymmetric tubes with variable circular cross section, and derives analytical expressions for the average pressure drop.
Article
Mechanics
Roger I. I. Tanner
Summary: This note discusses the author's interaction with Professor Hanswalter Giesekus and his rheological work.
Article
Mechanics
Roger I. Tanner
Summary: This paper discusses the yielding behavior of soft materials and presents experiments on two lubricating greases as examples. Similar to other experimenters, no evidence of the von Mises yield criterion was found, but the Tresca maximum shear stress criterion was occasionally applicable.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2022)
Article
Mechanics
Shaocong Dai, Roger I. Tanner
Summary: This study investigates strain reversing flow patterns in inelastic non-colloidal suspensions. The main finding suggests that the unlocking of the suspension structure occurs at a very small shear strain after a strain-rate reversal. It is also observed that the sudden drops in stress upon strain-rate reversal make it difficult to determine the linear behavior range of G' and G values in oscillatory flow.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2022)
Article
Mechanics
Kostas D. Housiadas
Summary: This study investigates the performance of two-point Pade approximants on the truncated series solutions for the shear and elongational viscosities of viscoelastic flows modeled with the Giesekus constitutive equation. Low- and high-order two-point diagonal Pade approximants are constructed and found to predict the right trends over the entire range of Weissenberg number, with the high-order formula being more accurate. The results demonstrate the analytical predictability of viscoelastic phenomena using the proposed two-point Pade non-linear analysis.
Article
Mechanics
Kostas D. Housiadas, Christos Tsangaris
Summary: In this study, the effect of Navier slip in the steady, laminar flow of a highly viscous and incompressible Newtonian fluid in a microfluidic channel with variable geometry is investigated. Analytical expressions in series form for the pressure drop are derived, and it is shown that slip at the walls substantially reduces the required pressure drop and facilitates fluid transport. Additionally, the higher-order terms in the asymptotic solution provide important information for the field variables and major quantities of interest in this type of internal and confined flows.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2023)
Article
Mechanics
Kostas D. Housiadas, Georgios C. Georgiou
Summary: We study the regularized Papanastasiou model in ducts, focusing on symmetric channels and axisymmetric pipes with varying walls. By using the classic lubrication approximation and the Lambert W function, we obtain exact analytical solutions for the isothermal, steady and creeping flow field. These solutions reduce to the analytical solutions for ideal yield-stress Bingham and Newtonian fluids under specific parameter values of the Papanastasiou model. The analytical solutions are then used to calculate the average pressure drop required to maintain constant volumetric flowrate through the duct, with emphasis on the effects of Bingham and regularization numbers, as well as the amplitude of undulation or wall variation.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2023)