a theoretical solution is presented for the forced convection heat transfer of a viscoelastic fluid obeying the giesekus constitutive equation in a concentric annulus under steady state, laminar, and purely tangential flow. a relative rotational motion exists between the inner and the outer cylinders, which induces the flow. a constant temperature was set in both cylinders, in this study. the f...

Many micro-organisms swim through gels and non-Newtonian fluids in their natural environments. In this paper, we focus on micro-organisms which use flagella for propulsion. We address how swimming velocities are affected in nonlinearly viscoelastic fluids by examining the problem of an infinitely long cylinder with arbitrary beating motion in the Oldroyd-B fluid. We solve for the swimming veloc...

the purpose of this research is to numerically investigate the interaction of pulsatile flow of blood with an axisymmetric artery in various percentages of stenosis. the carreau non-newtonian model and the generalized maxwell rheological model were used to model the blood fluid and the viscoelastic wall of arterial, respectively. the innovation of the present research is modeling of viscoelasti...

in this paper, nonlinear vibration and instability response of an embedded pipe conveying viscose fluid is investigated. the pipe is considered as a timoshenko beam embedded on an elastic foundation which is simulated by spring constant of the winkler-model and the shear constant of the pasternak-model. the external flow force, acting on the beam in the direction of the flexural displacement is...

A three-dimensional lattice Boltzmann model with thirty two discrete velocity distribution functions for viscoelastic fluid is presented in this work. The model is based upon the generalized lattice Boltzmann equation constructed in moment space. The nonlinear equilibria of the model have a number of coupling constants that are free parameters. The dispersion equation of the model is analyzed u...

The instability, rupture, and subsequent growth of holes in a thin Jeffreys-type viscoelastic film under the influence of long-range van der Waals force are investigated using both linear stability analysis and nonlinear numerical solutions. The linear stability analysis of full governing equations valid for arbitrary wave numbers shows that although fluid rheology does not influence the domina...

In this study prediction of the steady-state flow of branched polymer melts in pipe geometry with finite volume method is presented. Our analysis in this study revealed that;for normal-stress tqq , the XPP model can predict this tensor unlike the other viscoelastic models such as PTT or Gieskus which can not predict tqq...

in this paper, the transient inertial viscoelastic flow around a circular cylinder is investigated numerically. a second order finite-volume method is used to increase the numerical accuracy. here, the giesekus model is used as the constitutive equation. this nonlinear model has prominent ability in describing normal stress differences and viscosity in power-law regions. the impacts of the elas...