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Showing 1 to 20 of 37 for “"Viscoelastic Fluids"”.
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Design tools for linear viscoelastic fluids
… as hard, elastic solids and simple, Newtonian fluids. Rheologically-complex materials (non-Newtonian fluids and soft solids) demonstrate useful and novel properties in both engineered and biological systems. Incorporating these materials in rational engineering design stands to vastly enhance …
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Shear flow instabilities in viscoelastic fluids
… with the theoretical study of the stability of viscoelastic shear flows. It is divided into two parts: part I studies inertialess coextrusion flows at large Weissenberg number where the instabilities are due to discontinuities in the elastic properties, and part II studies the effect of …
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Numerical studies of Newtonian and viscoelastic fluids
… to understand the flow behavior of Newtonian and viscoelastic fluids in porous materials, four-to-one contraction and the flow of a Newtonian fluid past an airfoil. In simulations the viscoelastic fluid is modeled by the finitely extensible nonlinear elastic (FENE) dumbbell and Oldroyd-B models. …
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Effects of viscous dissipation on hydrodynamic stability of viscoelastic fluids
Two constitutive equations for viscoelastic fluids are examined in linearized hydrodynamic stability analysis for the effects of viscous dissipation, in plane Couette flow heated from below. All physical properties are assumed constant except the density in the body-force term of the momentum …
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Modeling the Motion of Solid Objects Immersed in Viscoelastic Fluids
Flows of viscoelastic fluids around immersed objects have long been a subject of interest in both experimental and theoretical studies. Such flows are used as benchmarking problems for validation of advanced numerical methods and the predictions of equations of state, as model systems for larger …
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Effect of Rolling on Viscoelastic Fluids Using a Novel Testing Device
… (10, 25, 48 and 91 mm/s) applied on the sample fluids for 10 cycles. We were able to examine the effect of different speeds within each load for each of the fluid that was tested. With higher speeds, the film thickness of both HA and synovial fluid appeared to decrease, which is an expected …
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The effect of viscoelastic fluids on flows generated by spherical objects during sedimentation
… of free-swimming organisms sedimenting in viscoelastic fluids and serve as a precursor to further experiments involving free-swimming organisms swimming in viscoelastic fluids. The post-processed data from these experiments are presented as colour maps in graphs of Reynolds number versus …
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Flow of viscoelastic fluids through banks of cylinders: an experimental and numerical investigation
… using purely viscous models or whether a viscoelastic constitutive equation is required. To predict these pressure drops, finite element calculations were performed using the generalized Newtonian fluid (GNF) model with the Bird-Carreau viscosity function, as well as two viscoelastic …
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Mini-Portable Rheometer: A device for the on-site rheological characterization of viscoelastic fluids
… on-site rheological characterization of complex fluids is important for a number of industrial, medical, and academic applications. Typically, laboratory-based rheometers are used to characterize rheological properties of fluids, which include, elasticity, relaxation time, and shear viscosity. …
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The stability of viscoelastic fluids in complex flows : the role of shear and extensional rheology
Understanding the flow of polymeric fluids is important for optimizing commercial processes such as injection molding and fiber spinning. The combination of streamwise curvature and elastic normal stresses can lead to the onset of elastic flow instabilities, severely rate-limiting such processes. …
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An experimental and theoretical study of the flow about spheres and discs rotating slowly in viscoelastic fluids
… diameter. Both Natrosol solutions exhibited viscoelastic behaviour in all cases. The Newtonian fluid study is at a Reynolds number of 1,2: all viscoelastic fluid studies are within the range of Reynolds numbers of 0,05 to 1,24. The zero shear viscosities of the Natrosol solutions are measured …
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Numerical Simulation Of Stratified Flows And Droplet Deformation In 2D Shear Flow Of Newtonian And Viscoelastic Fluids
We develop a viscoelastic version of the volume of fluid algorithm for tracking deformable interfaces. The code uses the piecewise linear interface calculation method to reconstruct the interface, the continuous surface force formulation to model interfacial tension forces and utilizes the …
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A study of a flapping flag in viscoelastic fluids and its implications for micro-scale swimming in biofluids
… of propulsion when in viscous, viscolelastic fluids rather than Newtonian fluids. By studying the dynamics of a flag under a flow of a viscoelastic fluid, we hope to better understand the swimming dynamics in these biological fluids. A slender polysiloxane rod was placed in a rotating annulus …
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The Stability Properties of Some Rheological Flows
… is investigated for a wide range of viscous and viscoelastic fluids. The effect of inertia, elasticity, temperature gradients, viscous heating and Biot boundary conditions are of particular interest. Both destabilisation and bifurcation phenomenon are found.<br/>For Newtonian constant viscosity …
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Complex fluid dynamical computations via the Finite Volume Method
Numerical simulations of the complex flows of viscoelastic fluids are investigated. The viscoelastic fluids are modelled, primarily, via the Johnson-Segalman constitutive model. Our Numerical approach is based on finite volume method, based on the Johnson-Segalman constitutive model and implemented …
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Computational analysis of viscoelastic fluid dynamics with applications to heat exchangers
… the computational analysis of a pressure driven viscoelastic fluid in a double pipe heat exchanger set-up is investigated. Non-Newtonian viscoelastic fluids in heat exchanger arrangements are encountered in various industrial applications such as power generation, refrigeration and in the food …
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Computational studies of viscoelastic multiphase flows
… direct numerical simulations (DNS) of viscoelastic two-phase flow problems. The Oldroyd-B constitutive equation is used to model the viscoelastic liquid. The code is used to study transient and steady state shapes of Newtonian and viscoelastic drops in simple shear and buoyancy driven …
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Controllability of the Stresses in Multimode Viscoelastic Fluid of Upper Convected Maxwell Type
Viscoelastic fluids, or Non-Newtonian fluids, are those that do not have a linear algebraic relation between the velocity field and the stresses arising in the media. Such fluids exhibit properties of both solids and liquids, and therefore cannot be modeled with methods of elasticity or Newtonian …
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X -Ray Diffraction Rotational Microrheology
… to find the storage and dissipative behavior of viscoelastic fluids of much higher viscosity than translational single particle tracking. The technique of X-ray diffraction rotational tracking has the ability to track the rotational motion of single crystals to a resolution of 80murad with a time …
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Simulation of blood flows in a stenosed and bifurcating artery using finite volume methods and OpenFOAM
… simulations of the complex flows of complex (viscoelastic) fluids are investigated. The primary fluid investigated in this thesis is human blood, a complex fluid which can be modelled via viscoelastic constitutive models. The most commonly used constitutive models for viscoelastic fluids …
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