Flow simulation 2012 technical reference 15 following boussinesq assumption, the reynoldsstress tensor has the following form. Steadystate nonnewtonian viscosities were observed at various constant stretch histories. We combine a slipspring model with an entangled kink dynamics ekd model for strong uniaxial extensional flows with rouse weissenberg number w i r. Solidworks flow simulation enables true concurrent cfd, without the need for advanced cfd expertise. In this approach, a highly strained polymer chain in extensional flow is modeled as a quasionedimensional chain with kinks at which the polymer folds back on itself. For instance, during jet breakup, or when a drop of pure water falls from a faucet or a nozzle, it suddenly necks down under. A priori determination of the extensional viscosity of. Roberto frias, 4200465 porto, portugal bdepartment of mechanical engineering, mit, 77 massachusetts avenue, cambridge, ma. Extensional rheometry of polymeric fluids and the uniaxial elongation of viscoelastic filaments. Good morning everyone, i found a pdf of flow simulation tutorial and i couldnt find the training files, so please anyone could just give me file named.
Pdf theory and simulation of extensional flowinduced. Larsona and hua hu department of chemical engineering, university of michigan, ann arbor, michigan 4810926 d. Webster 2 1sik the swedish institute for food and biotechnology, se40229 goteborg, sweden. The pressure drop is taken from the cfd simulation. Here is the kronecker delta function it is equal to unity when i j, and zero otherwise, is the dynamic viscosity coefficient, is the turbulent eddy viscosity. Modeling strong extensional flows of polymer solutions and melts antony n.
Nanosheets graphene, bnns, mx 2 are promising materials for a variety of materials and electronics applications. The excess pressure drop resulting from the converging and diverging flow is an important dynamic measure to quantify if the device is. Raphson and fast decoupled methods were compared for a power flow analysis solution. The unraveling dynamics of long, isolated, molecules of dna subjected to an extensional flow in a crossedslot device, single polymer dynamics in an elongational flow, science 276, 20162021 1997.
Estimation of elongational viscosity using entrance flow simulation debabrata sarkar and mahesh gupta mechanical engineeringengineering mechanics department michigan technological university houghton, mi 49931. Molecular dynamics simulation of liquid bridge extensional. Numerical simulation of extensional fault reactivation and fluid flow. Theory and simulation of extensional flowinduced biaxiality in discotic mesophases article pdf available in journal of physics b atomic and molecular physics 59 september 1995 with reads. Extensional rheometry of polymeric fluids and the uniaxial.
The slipspring model captures the dynamics up to the formation of a kinked or folded state, while the kink dynamics simulation tracks the. Gupta gs engineering plastic flow, llc houghton, mi 49931 houghton, mi 49931 abstract flows of a lowdensity polyethylene in a corotating twinscrew extruder and in a twelvescrew ring extruder are compared. Extensional flows may be generated within a flow field that experiences a sudden change in geometry, such as contractions, or orifice plates. Simulation of extensional flow through contractions towards a measuring system for extensional viscosity m. Brownian dynamics simulations of a dna molecule in an extensional flow field article pdf available in journal of rheology 432. Pdf simulations of extensional flow in microrheometric. Direct observation of dna dynamics in semidilute solutions. The ratio of elongational viscosity to shear viscosity, that is, trouton ratio, is no longer three, or even close to three. The need for appropriate rheological data pertaining to such flows represents a major obstacle to the development of improved process simulation. Brownian dynamics simulations of a dna molecule in an extensional. Online tutorials the introduction to flow analysis applications with solidworks flow simulation is a. For instance, the flow in the injection moulds where the crosssection is varying and the flow between twinscrew elements in. Good quantitative agreement with extensional flow data, and data on linear viscoelastic and viscometric properties, may usually be obtained only at the price of introducing a complicated equation that may present too great a challenge in the computational simulation of complex flows. Conformation hysteresis in extensional flow, science, 301, 15151519 2003 dna fractional extensiondna fractional extension.
A transient finite element scheme with a pressure correction method is employed to analyse the numerical treatment of such problems for oldroyd. Department of chemical and biomolecular engineering, university of tennessee. The polymer melt elasticity, high shear viscosity, extensional viscosity and its tendency to slip at the solid surfaces causes the flow destabilization. Peng propulsion division a study was made of the behavior of polyisobutylene under motion at a constant stretch history for both strip biaxial extensional flow and simple extensional flow. Direct observation of dna dynamics in semidilute solutions in extensional flow kaiwen hsiao department of chemical and biomolecular engineering, university of illinois at urbanachampaign, 600s. Effect of hydrodynamic interactions on dna dynamics in. This functionality is available for the hvac module users only.
D1 150w halogen floodligh d2 hospital room in the examples for electronics cooling module you can see how to use an additional capabilities of the flow simulation to simulate a wide variety of electronic. Multiphase flow 18, 1045 1992 could be used to perform simulations of this flow with arbitrary duration. Read molecular dynamics simulation of liquid bridge extensional flows, journal of nonnewtonian fluid mechanics on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Microstructure and thickening of dense suspensions under. We present a detailed numerical study of the flow of a newtonian fluid through microrheometric devices featuring a sudden contractionexpansion. Hyperbolic contraction flow is a suitable method for medium viscosity fluids. Simulations of extensional flow in microrheometric devices article pdf available in microfluidics and nanofluidics 56.
Polymer strands between the kinks are considered fully stretched and brownian force. In this simulation, the souza martins method is performed for driving the extensional shear coupled flow field, by combining the simple. The nonlinear transient extensional and steadystate shear rheological properties of dilute polystyrene solutions of molecular weight 3. Modeling hydrodynamic interaction in brownian dynamics. If the contractionexpansion geometry is abrupt, spatially inhomogeneous extensional behavior is observed in the entrance region, and this can make it difficult to identify a single constant strain rate. Molecular processes leading to necking in extensional. Pdf periodic boundary conditions for the simulation of. Mathews avenue, urbana, illinois 61801 chandi sasmal and j. Recent interest in extensional viscosity arises in part from the realization that, for polymeric liquids, the ratio of the extensional viscosity to the shear viscosity now commonly referred to as the trouton ratio can be significantly higher than 3, implying that in relative terms these liquids, particularly dilute polymer solutions, often show much more resistance to an extensional flow. For a polymer melt, the initial growth in the force can be retarded due to the absence of a solvent instantaneous viscosity, and experiments show that the filament fails i. The behavior of polymeric liquids and of suspensions of long slender particles fibre suspensions is markedly different in shear and extension. Modeling strong extensional flows of polymer solutions and. By imposing extensional and shear flows, we can assess the degree of flowtype dependence in regimes below and above thickening.
Introduction and theory any change in geometry during flow or processing of a nonnewtonian, viscoelastic liquid generates an. Orientation and dispersion evolution of carbon nanotubes. The numerical simulation of three model viscoelastic extensional flows is considered. Intramolecular hydrodynamic interactions hi in flexible polymer chains influence both the equilibrium and nonequilibrium physical properties of macromoecules. Modeling and simulation of dynamics of polymeric solutions. Both decoupled and coupled formulations are compared.
Extensional flow through hyperbolic contraction studied both numerically and experimentally m. Indian institute of technology bombay, mumbai, india introduction. In this work, we utilize a combination of single molecule experimental techniques and brownian dynamics bd simulation to investigate the role of hi and excludedvolume ev interactions for dna molecules ranging in contour length. Chu department of physics, stanford university, stanford, california 94305. Simulations of extensional flow in microrheometric devices. The ratio of capillary stress to extensional rate can be used for estimating this resistance to extensional flow, leading to the following formula for determining transient as well as steady, terminal extensional viscosity values from the radius evolution data. Simulation and single molecule experiment charles m. Using numerical simulation of extensional and shear flows, we investigate how rheological properties are determined by the microstructure that is built under flows and by the interactions between particles.
Macromolecular relaxation, strain, and extensibility. The extensional flow and breakup of liquid droplets are strongly affected by the presence of a very small amounts of long macromolecules. Hydrodynamics of viscoelastic jets in extensional flow. Hydrodynamics of viscoelastic jets in extensional flow s. Brownian dynamics simulations of a dna molecule in an.
Simulation of extensional flow through contractions. Analysis of the load flow problem in power system planning. Extensional flow fields are often present during dispersion processing, such as spin coating. Using the brownian dynamics simulation technique, we studied the fracture process of dna chains subjected to transient extensional flow, letting the solution with dna molecules pass through a very small orifice radius 0. Visualization of streamlines of the extensional flow. Model used to estimate extensional force the force applied onto a protein molecule was estimated using the elementary model for shear denaturation of a protein by elongational flow figure 7, ref 3.
Full hydrodynamic interaction is incorporated into bd simulations using the rotneprager tensor. Response of flexible polymers to a sudden elongational flow, science 281, 3540 1998 are predicted by brownian dynamics simulations using measured elastic and viscous. For the simulation of planar extensional flow it was recognized that the pbcs of kraynik and reinelt int. The extensional flow of viscoelastic flow is encountered during fibre spinning processes. Slipspring and kink dynamics models for fast extensional. Shaqfeh departments of chemical and mechanical engineeringdepartments of chemical and mechanical engineering. The main flow on the videos is from the right to the left whereas it was chosen to display all manuscript figures with a flow from the left to the right. The velocity is reported in simulation units of monte carlo sites mcs per. Effect of hydrodynamic interactions on dna dynamics in extensional flow. Joydeep mukherjee, department of chemical engineering, university of michigan. This paper presents analysis of the load flow problem in power system planning studies. Introduction the melt flow in polymer processing is a mixture of shear flow and extensional flow. Pdf brownian dynamics simulations of a dna molecule in.
An introduction to flow analysis applications with. Extensional flow through hyperbolic contraction studied. Multiscale modeling and simulation of polymeric liquids. Beris cscamm workshop multiscale modeling and simulation of complex fluids april 19, 2007 acknowledgements. This flow configuration is typically used to generate extensional deformations and high strain rates. Solidworks flow simulation student workbook 1 i introduction about this course the introduction to flow analysis applications with solidworks flow simulation and its supporting materials is designed to assist you in learning solidworks flow simulation in an academic setting. The introduction to flow analysis applications with solidworks flow simulation and its supporting materials is designed to assist you in learning solidworks flow simulation in an academic setting.
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