Article
Mechanics
Sayali N. Jadhav, Uddipta Ghosh
Summary: In this study, the settling of a drop in a quiescent viscous medium is analyzed to characterize interfacial phenomena in multiphase emulsions. The results show that stresses originating from interfacial rheology tend to decrease the settling velocity and make the surfactant concentration uniform across the surface. Furthermore, the settling velocity is found to be independent of the choice of free-energy isotherms and the extent of surfactant packing when variable diffusivity is correctly accounted for.
Article
Mechanics
Jae-Tack Jeong
Summary: This study investigates the axisymmetric slow viscous liquid flow around a spherical bubble located on the axis of a long circular tube analytically based on the Stokes approximation. Results include streamline patterns, pressure contour lines, drag exerted on the bubble, pressure change induced by the bubble, and drift velocity of the bubble due to the Hagen-Poiseuille flow. Additionally, the study discusses the appearance of viscous toroidal eddies and pressure distributions on the bubble surface.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2021)
Article
Mechanics
David F. James, Abhishek Tripathi
Summary: A previous study investigated the flow of Boger fluids in a converging channel, which was also used in this work to study the behavior of viscoelastic polymer solutions. Unlike other studies where the channel abruptly narrowed, causing a secondary motion and increased pressure drop, the slowly converging channel in this study confirmed the absence of upstream vortex. Measurements showed that at high flow rates, the pressure drop increased due to the formation of an upstream secondary motion, consistent with the literature.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2023)
Article
Multidisciplinary Sciences
M. R. Rezaie, M. Norouzi, M. H. Kayhani, S. M. Taghavi, Mirae Kim, Kyung Chun Kim
Summary: This study investigates the effect of fluid elasticity on axisymmetric droplets colliding with pre-existing liquid films, using both numerical and experimental approaches. The results indicate that the fluid's elasticity can enlarge the crown dimension at different thicknesses of the fluid film. Additionally, the extensional force in the crown wall can control the crown propagation at intermediate values of the Weissenberg number. Furthermore, the effects of the Weber number and the viscosity ratio on this problem are more significant at higher values of the Weissenberg number.
SCIENTIFIC REPORTS
(2023)
Article
Polymer Science
Salah A. Faroughi, Ana I. Roriz, Celio Fernandes
Summary: This study presents a framework based on machine learning models to predict the drag coefficient of a spherical particle in viscoelastic fluids. Three machine learning models (Random Forest, Deep Neural Network, Extreme Gradient Boosting) were trained, validated, and tested on two datasets generated using direct numerical simulations. The models achieved remarkable accuracy on the datasets, with XGBoost model performing the best. The generalization capability of the models was further assessed using a blind dataset, and the DNN model showed the highest accuracy. A meta-model was developed using stacking technique, outperforming the individual models on all datasets.
Article
Mechanics
Shivam Sahu, Aditya S. Khair
Summary: The study examines the deformation and breakup behavior of a neutrally-buoyant drop under oscillatory uniaxial extension at zero Reynolds number. Using boundary-integral computations, the evolution of the drop interface is calculated as a function of different parameters, revealing two main families of deformation behavior.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2022)
Article
Engineering, Environmental
Yong Chen, Pan Jiang, Ting Xiong, Wei Wei, Zhenlong Fang, Bin Wang
Summary: The study utilized the thermal lattice Boltzmann method to calculate drag coefficients and Nusselt numbers for nonspherical particles in uniform flow over a wide range of Reynolds numbers and aspect ratios. The results showed that the drag coefficient for ellipsoids and spherocylinders varied with the incident angle, while the Nusselt number for prolate ellipsoids was affected by the aspect ratio.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Engineering, Chemical
Huan-Chang Tseng
Summary: In capillary rheometry of a polymer melt, the total pressure drop is composed of shear viscosity, extensional viscosity, and normal stress differences. Viscoelastic constitutive equations have been traditionally used for accurate predictions, however, investigation of the primary components has been difficult in past experiments and computations. The improved White-Metzner viscoelastic constitutive equation coupled with weighted shear/extension viscosity is significant for the analysis of extension-induced and shear-induced pressure drops, along with a small contribution from normal stress differences.
INTERNATIONAL POLYMER PROCESSING
(2023)
Article
Engineering, Multidisciplinary
Pooja Jangir, Anushka Herale, Ratan Mohan, Paresh Chokshi
Summary: This study investigates the effects of incorporating polymer solutions on the viscous fingering patterns in flow displacement. The addition of polymers alters the viscosity contrast between fluids, leading to changes in fingering patterns. Furthermore, the shear-thinning behavior of the polymer promotes the longitudinal growth of fingers, while fluid elasticity inhibits finger growth and improves flow displacement efficiency.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2022)
Article
Thermodynamics
Mustafa Turkyilmazoglu
Summary: This study numerically simulates the flow induced by a radially expanding/contracting and rotating sphere with suction. It is found that wall suction affects the flow in different ways under various conditions.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2022)
Article
Biochemical Research Methods
Nan Xiang, Silin Wang, Zhonghua Ni
Summary: The device successfully addresses the competition between inertia effect and viscoelasticity effect by utilizing secondary flow to convert multi-train focusing into single-train focusing in low elasticity viscoelastic fluids. The effects of particle diameter, operational flow rate, polymer concentration, and channel dimension on particle focusing performances were systematically explored and discussed. The device enables single-train focusing of particles in viscoelastic fluids with low elasticity, offering advantages of planar single-layer structure, and sheathless, external-field free operation.
Article
Multidisciplinary Sciences
M. G. E. Roach, Herbert E. Huppert
Summary: This article analyzes the motion of an axisymmetric drop between two rotating discs. By making modeling assumptions and investigating the squeezing and contraction problems, the authors find solutions and identify critical values under specific conditions.
Article
Mechanics
Joel R. Karp, Ernesto Mancilla, Fabricio S. da Silva, Dominique Legendre, Roberto Zenit, Rigoberto E. M. Morales
Summary: The behavior of compound drops rising at high Reynolds numbers was studied experimentally, revealing two rising regimes with different governing effects. It was found that small internal bubbles lead to stable paths, while large internal bubbles result in oscillatory motion with diminished viscous effects. Models based on dimensionless numbers showed good agreement with the experimental measurements.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2021)
Article
Geosciences, Multidisciplinary
Qiu Yin, Ci Song
Summary: A new explicit approximation model of terminal settling velocity (TSV) for drops and spherical objects in fluid medium is established, which shows improved accuracy compared to past theoretical and empirical models. This model can adapt to different particle and medium parameters across a wide range of Reynolds numbers (Re).
FRONTIERS OF EARTH SCIENCE
(2021)
Article
Physics, Multidisciplinary
Atul Kumar Shukla, Mukesh Kumar Awasthi, Shivam Agarwal
Summary: The present study investigated the stability of a spherical interface formed by a combination of a viscous fluid and an Oldroyd B viscoelastic fluid using linear stability analysis. The study found that the stability of the interface increases with an increase in the viscoelasticity of the fluid.
CHINESE JOURNAL OF PHYSICS
(2023)
Article
Mechanics
Mateus C. Guimaraes, Fernando T. Pinho, Carlos B. da Silva
Summary: A new theory is proposed to describe the conformation state of polymer chains in free turbulent shear flows of viscoelastic fluids. The theory shows the existence of minimum and maximum solvent dissipation reduction asymptotes and four different polymer deformation regimes, based on self-similarity arguments and new scaling relations for the turbulent flux of conformation tensor. In addition, analytical solutions for the self-similar transverse profiles of the conformation tensor components are obtained. The theory is validated through excellent agreement with direct numerical simulations employing the FENE-P rheological model.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2024)
