Bingham Fluid Flow Research Articles

An augmented Lagrangian approach to simulating yield stress fluid flows around a spherical gas bubble

SUMMARYWe simulated the flow of a yield stress fluid around a gas bubble using an augmented Lagrange approach. The piecewise linear equal‐order finite elements for both the velocity and the pressure approximations proposed and analyzed by Latché and Vola in 2004 were applied. A mesh adaptive strategy based on this element‐pair choice was also proposed to render the yield surfaces of desired resolution. The corresponding numerical scheme was formulated for general Herschel–Bulkley fluids. Numerical results on Bingham fluid flows around a slowly rising spherical gas bubble were provided to validate the proposed algorithm. Copyright © 2011 John Wiley & Sons, Ltd.

A mixed formulation of the Bingham fluid flow problem: Analysis and numerical solution

In this paper we introduce a mixed formulation of the Bingham fluid flow problem. We consider both the original and a regularized version of the problem, where a parameter ε is introduced, forcing the entire domain to be formally a fluid region. In general, common solvers for the regularized problem experience a performance degradation when the parameter ε gets smaller. The method studied here introduces an auxiliary tensor variable and shows enhanced numerical properties for small values of ε. A good performance is also observed for the non-regularized case. The well posedness for the regularized problem and the equivalence – at the continuous level – between the original (primitive variables) and the mixed formulation are demonstrated. We analyze properties of linearized problems that are relevant for the convergence of numerical solvers. A finite element method for the mixed formulation is discussed. Numerical results confirm the predicted better performances of the mixed formulation when compared to the primitive variables formulation. A comparison to a non-regularized solver based on the augmented Duvaut–Lions–Glowinski formulation of the problem is carried out as well.

Bingham fluid simulation with the incompressible lattice Boltzmann model

The Bingham fluid flow is numerically studied using the lattice Boltzmann method by incorporating the Papanastasiou exponential modification approach. The He–Luo incompressible lattice Boltzmann model is employed to avoid numerical instability usually encountered in non-Newtonian fluid simulations due to a strong non-linear relationship between the shear rate tensor and the rate-of-strain tensor. First, the value of the regularization parameter in Bingham fluid mimicking is analyzed and a method to determine the value is proposed. Then, the model is validated by pressure-driven planar channel flow and planar sudden expansion flow. The velocity profiles for the pressure-driven planar channel flow are in good agreement with analytical solutions. The calculated reattachment lengths for a 2:1 planar sudden expansion flow also agree well with the available data. Finally, the Bingham flow over a cavity is studied, and the streamlines and yielded/unyielded regions are discussed.

Axial Couette–Poiseuille flow of Bingham fluids through concentric annuli

In this paper, the axial Couette–Poiseuille flow of Bingham fluids through concentric annuli is studied. Analytical solutions of different types of flow are derived. Compared to previous studies, we emphasize two new types of flow, which have been missed previously, are found in our results. Hence, there are eight different forms of the velocity profile depending on values of three dimensionless parameters, which are the Bingham, axial Couette numbers and the radius ratio. Distributions of these eight forms are specified in the parameter plane of axial Couette number vs. Bingham number for various radius ratios. These new flow regimes are analyzed from both a mathematical and physical perspective.

An augmented Lagrangian approach to Bingham fluid flows in a lid-driven square cavity with piecewise linear equal-order finite elements

We study an augmented Lagrangian approach to Bingham fluid flows in a lid-driven square cavity. The piecewise linear equal-order finite element spaces for both the velocity and the pressure approximations, proposed and analyzed by Latché and Vola [18], are applied. Based on the resulting regularity of the numerical solutions, a mesh adaptive strategy is proposed to render the yield surfaces of desired resolution. The corresponding numerical scheme is formulated for general Herschel–Bulkley models, and its validity is verified on the benchmark model: Bingham fluid flows in a lid-driven square cavity.

Numerical simulation of Taylor Couette flow of Bingham fluids

The Bingham fluid flow between two concentric cylinders is studied using numerical simulation. The cylinders are assumed to rotate independently, and with an imposed axial sliding. The flow field is decomposed with linearity arguments of the base circular Couette shear flow and corresponding deviation field. The numerical methods are based on the expression of the deviation field in terms of complete sets of orthogonal functions and Chebyshev series. The Galerkin projection method is used with the pressure term being eliminated. The Adams Bashforth scheme is adopted for time marching. The results show that the vortices are squeezed toward the inner cylinder due to the effect of yield stress. When the outer cylinder is held stationary, the yield stress plays a role in weakening the vortex flow. However, for the co-rotation situation, the vortex flow is initially strengthened with an increase of yield stress, and then weakened as the yield stress is raised large enough. The annular unyielded regions emerge and stick to the outer cylinder. In case of Taylor Couette flow with an imposed axial sliding, a spiral vortex flow is visible with spiral unyielded region being obtained.

Numerical simulation of the start-up of Bingham fluid flows in pipelines

This paper describes a mathematical model used to simulate the restart of an axial, compressible and transient flow of a Bingham fluid in circular or annular pipes. The model is based on the mass and momentum conservation equations plus a state equation that relates pressure to density. The viscous effect is modeled by employing a friction factor approach. The governing equations are discretized by using the finite volume method with a first-order upwind scheme, and the resulting non-linear algebraic equations are then solved iteratively. The model results were corroborated by an analytical solution for Newtonian flows. Additionally, the results were also in reasonable agreement with results reported in the literature. We also conducted sensitivity analyses with respect to Reynolds number, aspect ratio, gravity and the non-linear advective terms of the governing equations.

Approximate explicit analytical expressions of friction factor for flow of Bingham fluids in smooth pipes using Adomian decomposition method

This study concerns with the development of explicit expressions of friction factor for the flow of Bingham fluids in smooth pipes in both laminar and turbulent regimes by using a powerful analytical technique, i.e. Adomian decomposition method (ADM) and one of its variant namely restarted ADM (RADM). The results from these expressions match very well with those obtained by well-known correlations and are found to be valid for all practical ranges. It is hoped that the derived expressions will be useful for the researchers working in the area.

Numerical simulation of two-dimensional Bingham fluid flow by semismooth Newton methods

This paper is devoted to the numerical simulation of two-dimensional stationary Bingham fluid flow by semismooth Newton methods. We analyze the modeling variational inequality of the second kind, considering both Dirichlet and stress-free boundary conditions. A family of Tikhonov regularized problems is proposed and the convergence of the regularized solutions to the original one is verified. By using Fenchel’s duality, optimality systems which characterize the original and regularized solutions are obtained. The regularized optimality systems are discretized using a finite element method with (cross-grid P 1 )– Q 0 elements for the velocity and pressure, respectively. A semismooth Newton algorithm is proposed in order to solve the discretized optimality systems. Using an additional relaxation, a descent direction is constructed from each semismooth Newton iteration. Local superlinear convergence of the method is also proved. Finally, we perform numerical experiments in order to investigate the behavior and efficiency of the method.

A numerical study of the flow of Bingham-like fluids in two-dimensional vane and cylinder rheometers using a smoothed particle hydrodynamics (SPH) based method

In this paper, a Lagrangian formulation of the Navier–Stokes equations, based on the smoothed particle hydrodynamics (SPH) approach, was applied to determine how well rheological parameters such as plastic viscosity can be determined from vane rheometer measurements. First, to validate this approach, a Bingham/Papanastasiou constitutive model was implemented into the SPH model and tests comparing simulation results to well established theoretical predictions were conducted. Numerical simulations for the flow of fluids in vane and coaxial cylinder rheometers were then performed. A comparison to experimental data was also made to verify the application of the SPH method in realistic flow geometries. Finally, results are presented from a parametric study of the flow of Bingham fluids with different yield stresses under various applied angular velocities of the outer cylindrical wall in the vane and coaxial cylinder rheometers. The stress, strain rate and velocity profiles, especially in the vicinity of the vane blades, were computed. By comparing the calculated stress and flow fields between the two rheometers, the validity of the assumption that the vane could be approximated as a cylinder for measuring the rheological properties of Bingham fluids at different shear rates was tested.

Creeping flow around particles in a Bingham fluid

We revisit the variational setting of the creeping flow of Bingham fluid about a particle. We investigate two problems: the resistance and the mobility problem, which arise in the context of sedimentation. We present results and the general framework for uniqueness, symmetry and reversibility properties of solutions, and clarify the relation between resistance and mobility problems. We also consider general properties of the static stability limit (or load limit). In the second part of the paper we apply insights gained from the first part to the computation of 2D exterior flow around an infinite cylinder with elliptical cross-section. We study the static stability limit and find that the limiting flow solution approaches the perfectly plastic solid solution.

S0501-1-4 粘弾性流体における管内流動の特性評価([S0501-1 ]複雑流体の流動現象(1))

S0501-1-4 粘弾性流体における管内流動の特性評価([S0501-1 ]複雑流体の流動現象(1))

Finite-difference schemes for the computation of viscoplastic medium flows in a channel

Two finite-difference schemes for the computation of incompressible Bingham fluid flows in pipes are proposed. The variational Duvaut-Lions inequality is used as a mathematical model. One of the difference schemes is an analogue of the well-known MAC (marker-and-cell) scheme on staggered grids, the second employs one grid for velocity approximation, and the other for all the components of the strain rate tensor. The convergence of finite-difference schemes and the iteration method are studied. The obtained results are compared with those known from publications. The proposed schemes were used to compute Bingham medium with an inhomogeneous yield stress.

Application of the Lambert W function to steady shearing flows of the Papanastasiou model

Using the Lambert W function, the constitutive relation of the Papanastasiou model is inverted so that the second invariant of the first Rivlin–Ericksen tensor can be expressed as a function of the second invariant of the extra stress tensor. In steady shearing flows, this results in the magnitude of the shear rate becoming a function of the magnitude of the shear stress. Since the distribution of the latter is known explicitly in channel, Poiseuille and Couette flows, one can investigate the nature of analytical solutions in these flows. It is shown that explicit answers are found for channel and Poiseuille flows only, with the Couette flow requiring a numerical solution in general. From the channel flow results, it is obvious that there is a great amount of congruence between the predictions of the Papanastasiou model and the Bingham fluid. In turn, this lends further confidence to the application of the Papanastasiou model to study the flows of Bingham fluids.

Two finite-difference schemes for calculation of Bingham fluid flows in a cavity

Two finite-difference schemes are proposed in the paper for the calculation of a viscous incompressible Bingham fluid flow. The Duvaut–Lions variational inequality is considered as a mathematical model of the medium. One of the finite-difference schemes is a generalization of the well-known MAC scheme on staggered grids. The other scheme uses one grid for approximation of all velocity components and another grid for all components of the rate of deformation tensor and pressure. A special stabilizing term is introduced into this scheme, which provides stability and preserves the second order of convergence of the scheme. Additional consistency conditions for grid operators are introduced, which are necessary for the correctness of the difference method. The numerical solution of the problem of the Bingham fluid flow in a cavity is considered as a model example.

Couette–Poiseuille flow of Bingham fluids between two porous parallel plates with slip conditions

Analytical solutions of Couette–Poiseuille flow of Bingham fluids between two porous parallel plates are derived. This study extends the work of Tsangaris et al. [S. Tsangaris, C. Nikas, G. Tsangaris, P. Neofytou, Couette flow of a Bingham plastic in a channel with equally porous parallel walls, J. Non-Newtonian Fluid Mech. 144 (2007) 42–48] to a general situation where the slip effect at the porous walls is considered. It is found that the form of the flow inside the channel depends not only on the Bingham number Bn, the Couette number Co (related to the moving wall) and the transverse Reynolds number Re, but also on the slip parameter Cs at the porous walls. In both the Co– Re diagram and the Co– Bn diagram, the region where plug flow appears enlarges as the slip effect increases, especially in the case where Co is negative. In the case where plug flow and double shear flow coexist, the transverse position of the plug flow and the shear rate at the boundaries exhibit two opposite behaviors when Cs increases, depending on the value of the other three dimensionless numbers. In other cases, slippage always weakens the shearing deformation of the flow.

Lattice-Boltzmann method for yield-stress liquids

In the present study we propose a new version of the lattice-Boltzmann (LB) method for the simulation of flow of yield-stress liquids. Unlike traditional LB methods, collisions are treated implicitly, i.e., the collision term is chosen in such a way that the stress and strain rate tensors satisfy the constitutive equation after the collision. This approach requires the solution of a (one-dimensional) non-linear algebraic equation at each point and at each time step. In the practically important cases of a Bingham liquid this equation can be solved analytically. We calculated the flow of Bingham fluid through a channel and periodic mesh of cylinders.

Buoyant Couette–Bingham flow between vertical parallel plates

The present paper is closely related to a recent work of Bayazitoglu et al. [Y. Bayazitoglu, P.R. Paslay, P. Cernocky, Laminar Bingham fluid flow between vertical parallel plates, Int. J. Thermal Sci. 46 (2007) 349–357], in which the free convection of a Bingham material in a vertical parallel plane channel with a constant temperature differential across the walls has been investigated. Our interest is directed on the additional effect of an external shear, applied on the wall–fluid interface. This forcing shear is induced (in our mathematical model) by a uniform vertical motion of the hot wall of the channel in its own plane. The physically most interesting five-domain configuration of the velocity field of the resulting buoyant Couette–Bingham flow is examined in detail. For the initiation temperature of the flow, whose existence has been predicted in [Y. Bayazitoglu, P.R. Paslay, P. Cernocky, Laminar Bingham fluid flow between vertical parallel plates, Int. J. Thermal Sci. 46 (2007) 349–357], a generally valid formula is reported. Subsequently, it is shown that the core velocities with rigid body motion depend on the wall velocity sensitively. The hot and cold cores possess the same width which, however, decreases with increasing wall velocity rapidly. There always exists a critical downward pointing wall velocity for which the upward motion of the hot core is dropped.

Modal and non-modal linear stability of the plane Bingham–Poiseuille flow

The receptivity problem of plane Bingham–Poiseuille flow with respect to weak perturbations is addressed. The relevance of this study is highlighted by the linear stability analysis results (spectra and pseudospectra). The first part of the present paper thus deals with the classical normal-mode approach in which the resulting eigenvalue problem is solved using the Chebychev collocation method. Within the range of parameters considered, the Poiseuille flow of Bingham fluid is found to be linearly stable. The second part investigates the most amplified perturbations using the non-modal approach. At a very low Bingham number (B ≪ 1), the optimal disturbance consists of almost streamwise vortices, whereas at moderate or large B the optimal disturbance becomes oblique. The evolution of the obliqueness as function of B is determined. The linear analysis presented also indicates, as a first stage of a theoretical investigation, the principal challenges of a more complete nonlinear study.

Squeeze flow of Bingham fluids under slip with friction boundary condition

This paper develops a theoretical analysis of a Bingham fluid in slipping squeeze flow. The flow field decomposition consists in combining a central extensional flow zone in the plane of symmetry and shear flow zones near the plates. It is also considered that the slipping zone is located around a central sticking zone as previously shown from experiments. It is assumed that the shear stress at the plates is constant in the slipping zone and equals a fixed friction yield value. The squeeze force required to compress a Bingham fluid under the slipping behaviour as well as the radial evolution of the transition point between both sticking and slipping zones are finally determined.