Pith. sign in

REVIEW 2 major objections 5 minor 83 references

The non-homogeneous flow of a thixotropic fluid around a sphere

T0 review · 2 major / 5 minor · reviewed 2026-08-14 · deepseek-v4-flash

Pith's one-line read A sphere falling through a thixotropic fluid keeps a partially structured wake at high speed, so its drag plateaus near 15 percent of the fully structured value instead of collapsing to the fully broken limit.

desk verdict A clean three-regime picture for thixotropic settling, with one load-bearing caveat: the terminal plateau sits in a regime where the Stokes assumption is no longer obviously valid. read the letter →

arxiv 1908.04993 v2 pith:T4T4ANNR submitted 2019-08-14 physics.flu-dyn cond-mat.soft

classification physics.flu-dyncond-mat.soft
keywords thixotropyMooremodelstructureparametersettlingspheredragcoefficientconvectiongeneralizedNewtonianfluidconfinedStokesflow
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper asks what happens to a sphere sedimenting through a thixotropic fluid when the flow field is not homogeneous, and it answers with a single drag-coefficient curve. Simulating the Moore structure-kinetics model in axisymmetric Stokes flow, it identifies three regimes as the normalized fall speed $U^*$ grows: a Newtonian-like regime where Brownian recovery holds the structure intact, a transient regime where shear breaks structure unevenly around the sphere, and a terminal regime where the drag coefficient $C_s$ levels off near $0.15$ rather than falling to the fully broken limit $\xi=0.00990$. The reason is that convection of fully structured fluid from upstream replenishes the destroyed microstructure faster than local recovery could, so the fluid never reaches its completely broken state. This matters because it gives a measurable signature that separates true thixotropy from purely shear-rate-dependent (generalized Newtonian) behavior and shows that geometry, not just material parameters, sets the effective resistance.

What carries the argument

The central object is the structure parameter $\lambda(x)$, whose steady distribution is set by $(u\cdot\nabla)\lambda + k_d\dot{\gamma}_s\lambda - k_a(1-\lambda)=0$, with viscosity $\eta(\lambda)=\eta_\infty+\eta_{\mathrm{str}}\lambda$. The paper solves this coupled advection-reaction structure equation with a discontinuous Galerkin discretization using upwind fluxes inside a Picard iteration around a Stokes solver on an axisymmetric sphere-in-tube domain. Two dimensionless quantities carry the argument: $U^*=(k_d/k_a)U/a$, which compares shear-induced breakdown with Brownian recovery, and $C_s$, the drag normalized by the fully structured Newtonian value including the Faxen wall factor $K$. The convection term in the structure equation is what lets structured fluid arrive from the inlet and prevents $\lambda$ from collapsing to zero at large $U^*$.

What would settle it

Measure the drag of a calibrated sphere settling in a well-characterized Moore-type thixotropic fluid across $U^*$ from 0.01 to 1000 at fixed confinement; if $C_s$ falls below about 0.10 toward $\xi=0.00990$ at large $U^*$, the convection-balance plateau is falsified. A companion check is to probe the wake structure directly, since the explanation requires a visibly partially structured ($\lambda$ well above zero) wake at $U^*\gg 1$.

Watch

Extended reading notes

Core claim

The paper claims that in steady Stokes flow around a settling sphere, a Moore thixotropic fluid cannot reach its fully broken state at high falling speeds. Although steady simple shear would drive the structure parameter $\lambda$ to nearly zero and the viscosity to $\eta_\infty$, the sphere flow does not: convection brings fully structured ($\lambda=1$) fluid from upstream faster than shear can destroy it, so a partially structured region, especially the wake, survives. As a result the drag coefficient $C_s = D/[K\,6\pi(\eta_\infty+\eta_{\mathrm{str}}) a U]$ follows a sigmoid with $U^* = (k_d/k_a)U/a$ and levels off near $C_s\approx 0.15$, roughly fifteen times the fully broken floor $\xi=\eta_\infty/(\eta_\infty+\eta_{\mathrm{str}})=0.00990$. The same balance explains why the flow at $U^*=200$ is fore-aft asymmetric and why pressure drag is about twice the viscous drag, the opposite of the Newtonian creeping-flow partition.

Load-bearing premise

The load-bearing premise is that creeping Stokes flow remains the right momentum balance throughout the $U^*$ sweep; at the fastest speeds the paper estimates local Reynolds numbers up to 0.8, so inertia could alter the plateau.

Editorial extensions

If this is right

  • If the plateau is real, drag at high terminal velocities grows linearly with speed but with effective viscosity roughly $0.15(\eta_\infty+\eta_{\mathrm{str}})$, so standard Stokes-calibrated settling estimates would overpredict the resistance and underpredict the settling time.
  • A finite destruction parameter $k_d$ is what separates thixotropic behavior from a generalized Newtonian Cross fluid in this geometry: at large $U^*$ the Cross fluid falls to $\xi$, while the thixotropic fluid stays on the plateau, and increasing $k_d$ pulls the plateau down toward $\xi$.
  • Confinement changes not only the plateau level but also the shape of the transient regime: a larger $a/R$ makes $C_s$ drop earlier and to a lower floor, so flow geometry can be tuned to control effective thixotropic resistance without changing the material.
  • If nonlinearity is added to the viscosity function ($\eta=\eta_\infty+\eta_{\mathrm{str}}\lambda^2$), the plateau moves to about $0.095$ but stays far above $\xi$; if instead a quadratic shear term is added to the kinetics equation, the structure eventually breaks fully and the drag approaches the Newtonian $\eta_\infty$ limit.
  • The plateau level itself encodes the balance between breakdown and convection, so it provides a single-number diagnostic for how strongly microstructure is being replenished in any given flow geometry.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • Editorial inference: A direct test of the mechanism is to run the same fluid in a closed recirculating geometry, where the upstream fluid has already been sheared; the plateau should shrink or vanish because convection can no longer supply fresh structure from an undisturbed reservoir.
  • Editorial inference: The ratio $C_s^{\mathrm{plateau}}/\xi$ could serve as a practical convective-compensation factor for a thixotropic fluid in a chosen geometry, measurable from a settling curve and useful for process design without needing full structure-field measurements.
  • Editorial inference: The paper's own Reynolds estimate reaches up to about 0.8 in the fastest cases, so the precise plateau value may shift once inertia is included; repeating the sweep at matched low Reynolds numbers by raising the fluid viscosity would isolate the thixotropic-convection contribution from inertial drag.
  • Editorial inference: For non-spherical particles or bubbles the stagnation-point and wake topology changes, so the plateau level should depend on shape; this could make the high-$U^*$ plateau a shape-sensitive fingerprint of thixotropic microstructure.
Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

2 major / 5 minor

Summary. The paper presents numerical simulations of steady creeping flow of a Moore-type thixotropic fluid around a settling sphere in a cylindrical tube. The structure-kinetics equation (7) is solved with a discontinuous Galerkin method coupled to Stokes equations (5)-(6) through a viscosity that depends on the structure parameter λ. Based on the normalized velocity U* = t_c U/a, the paper identifies three regimes: a Newtonian-like regime at U* << 1, a transient regime, and a terminal regime at U* >> 1 in which the drag coefficient C_s (defined by Eq. (17)) approaches a plateau near 0.15 rather than the fully-broken limit ξ = 0.00990. The plateau is attributed to a balance between shear-induced structure breakdown and the convection of fully-structured fluid from upstream, in contrast to the homogeneous limit where Brownian recovery alone is balanced. The paper also studies the effects of the destruction parameter k_d, the viscosity ratio ξ, the confinement ratio a/R, and two forms of nonlinear model modifications.

Significance. If the terminal-plateau mechanism is correct, the paper provides a concrete, falsifiable prediction: in non-homogeneous thixotropic flow, the drag coefficient does not approach the fully-broken viscosity ratio ξ as U* grows, because convection of unbroken structure from upstream sustains a finite effective viscosity near the sphere. This is a useful conceptual step beyond homogeneous rheometry for interpreting settling and processing flows. The numerical scheme is verified by a manufactured-solution test showing third-order convergence (Appendix A), and the model parameters (Table 1) are generic, not fitted to the reported drag, so the plateau is a genuine model output rather than a fitted curve. The main limitation is that the central plateau claim is computed under the Stokes assumption in a regime where local Reynolds numbers may not be small, and the paper does not provide a mesh-refinement study for the actual settling problem. These issues are examined in the major comments.

major comments (2)
  1. [Section 3, Figure 5(b)] The central claim that C_s plateaus near 0.15 for U* >> 1 rests on solutions of the Stokes equations (5)-(6), but the terminal regime is explored in a range where the creeping-flow assumption is questionable. With the paper's own parameters (ρ_f ≈ 1000 kg/m^3, a = 0.025 m, t_c = 10 s), U* = 100 and 1000 correspond to U = 0.25 and 2.5 m/s. In the strongly broken region near the sphere the viscosity approaches η_∞ = 1 Pa·s, giving local Re = ρ_f U a / η ≈ 6 and 62, respectively; even at the lower edge of the claimed plateau, U* = 10 (U = 0.025 m/s), the fully-broken value gives Re ≈ 0.6. The paper's statement that Re is at most 0.8 is based on a viscosity of 100–15 Pa·s, which is not representative of the thin broken layer that controls the drag. If inertia is included, u and γ̇_s no longer scale linearly with U, so the structure balance (7) is no longer independent of U and the plateau in C_s may be an artifact of the Stokes assumption. Please add either (i) inertial (Navier–Stokes) simulations for at least a few high-U* cases to test whether the plateau persists, or (ii) a posteriori Re-field evaluation with a clear statement of the U* range in which Re < 0.1, and restrict the plateau claim accordingly.
  2. [Section 2.4 and Appendix A] The manufactured-solution test in Appendix A confirms the formal third-order convergence of the discretization, but it does not establish that the reported C_s values—particularly the terminal plateau near 0.15—are mesh-converged on the 49,152-element mesh used for all results. The structure equation is a hyperbolic advection-reaction equation with sharp structure gradients near the sphere (e.g., Fig. 3c), and the drag integral (13) depends sensitively on near-sphere resolution. Please provide a mesh-refinement study for at least two representative conditions (e.g., U* = 0.1 and U* = 100) demonstrating that C_s changes by less than a few percent between the two finest meshes. Without this, the quantitative plateau values reported in Figures 5, 8, 9, 11, and 13 should be treated as tentative.
minor comments (5)
  1. [Section 3, Figure 5] The terminal value of C_s is reported inconsistently: the text says it converges to 0.15, while the caption of Figure 5(b) states C_s = 0.143, and later figures quote 0.104 and 0.194 without explaining how these constants are extracted. Please harmonize the numbers and state the criterion used to identify the plateau value.
  2. [Section 3, Figure 5(a)] The x-axis of Figure 5(a) extends only to U = 1 m/s, but the terminal regime at U* = 10^3 corresponds to U = 2.5 m/s with the given a and t_c, so the claimed linear D-U dependence in the terminal regime is not visible in the plot. Please extend the axis or add an inset.
  3. [Section 2.3] The normalized velocity is defined as U* = t_c U/a in Eq. (15), but figure axes use the equivalent expression U* = (k_d/k_a a) U (e.g., Figure 5b). Please use a single notation throughout and define it once in the text.
  4. [Abstract and Section 6] The phrase 'thixotropy fluid' in the abstract should be 'thixotropic fluid', and 'Discontinous Galerkin' in Section 6 should be 'Discontinuous Galerkin'.
  5. [Appendix A] The manufactured solution for λ (Eq. A.4) is unbounded and exceeds the physical range λ ∈ [0,1]; the authors correctly note this is acceptable for code verification, but a bounded manufactured solution would also exercise the physical constraints and the upwind treatment at boundaries more realistically.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the terminal plateau in Cs is an emergent simulation output, and the model parameters are not fitted to the reported drag behavior.

full rationale

The paper's central claims—the three flow regimes and the terminal plateau near Cs ≈ 0.15 at U* >> 1—are outputs of the coupled Stokes-flow / structure-kinetics solver, not inputs. The four model parameters in Table 1 (η∞=1 Pa·s, ηstr=100 Pa·s, ka=0.1 s⁻¹, kd=1) are chosen as a generic thixotropic fluid and are not calibrated to any drag measurement; the Cs–U* curve and the plateau value emerge from the simulation. The large-U* plateau is additionally supported by an independent scaling argument based on Eq. (7): after non-dimensionalization, the Brownian recovery term is O(1/U*) and drops out, leaving the U*-independent balance (u·∇λ) + kd γ̇s λ = 0 in Stokes flow. This explains, rather than presupposes, the numerically observed plateau. The two author-overlapping citations (refs 37 and 53) are used only to point to prior numerical procedures and prior use of the Moore model; they provide no fitted parameter, no uniqueness theorem, and no definition of Cs, so they are not load-bearing. The paper’s own acknowledgment that the Reynolds number may reach ≈0.8 at high U* (Sec. 3) is a validity limitation for the Stokes assumption, not a circularity. No derivation reduces to its own input by construction, and no fitted quantity is relabeled as a prediction.

Assumptions & free parameters 5 free parameters · 5 assumptions · 0 invented entities

The paper is a numerical parametric study of a model thixotropic fluid. The main free inputs are the four Moore model parameters chosen in Table 1; varying them changes the quantitative values of the drag plateau but not the qualitative three-regime picture. The Stokes, steady, axisymmetric, and full-inlet-structure assumptions are the main physical axioms. No new physical entities are introduced.

free parameters (5)
  • eta_infinity (residual viscosity) = 1.0 Pa.s
    Chosen in Table 1 for a generic thixotropic fluid; not fitted to any target result. The quantitative values of the drag plateau depend on this choice.
  • eta_str (structural viscosity) = 100.0 Pa.s
    Chosen in Table 1; sets the viscosity ratio xi = 0.0099.
  • ka (Brownian recovery rate) = 0.1 s^-1
    Chosen in Table 1; sets the recovery timescale and affects the definition of U*.
  • kd (destruction parameter) = 1.0 (dimensionless)
    Chosen in Table 1; varied in Sec 4.1 (kd = 0.1, 8).
  • kd2 (nonlinear kinetic coefficient) = 1.0 s
    Introduced in Sec 5 for the nonlinear structure-kinetics model (32); set arbitrarily.
assumptions (5)
  • domain assumption Stokes flow (Re << 1) applies for all simulated U*
    Used to write the momentum equation (5) without inertial terms. At the largest U* values, the local Reynolds number may exceed the Stokes regime, as the authors acknowledge in Sec. 3.
  • domain assumption Steady state (d/dt = 0) is reached
    All equations are solved as steady boundary value problems; the physical settling process may involve transient aging and history effects.
  • domain assumption Axisymmetric flow in a cylindrical tube
    Reduces the three-dimensional problem to a two-dimensional one (ur, uz); stated in Sec. 2.2.
  • domain assumption Fully structured fluid enters at the upstream boundary (lambda = 1)
    Boundary condition (12) imposes lambda = 1 at z = -L/2; this assumes the upstream fluid has not been sheared and has fully recovered.
  • domain assumption Linear Moore model captures generic thixotropy
    The paper deliberately uses a simple four-parameter model (Eqs. 1 and 3) and later tests two nonlinear variants. Real thixotropic materials may require more complex models with elasticity or yield stress.

how reviews work

0 comments
Cite this review

Pith. "Pith review of The non-homogeneous flow of a thixotropic fluid around a sphere." pith.science (2026). https://pith.science/paper/T4T4ANNR

@misc{pith2026190804993,
  author       = {Pith},
  title        = {Pith review of: The non-homogeneous flow of a thixotropic fluid around a sphere},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/T4T4ANNR}},
  note         = {Machine review of arXiv:1908.04993}
}
abstract

The non-homogeneous flow of a thixotropic fluid around a settling sphere is simulated. A four-parameter Moore model is used for a generic thixotropic fluid and discontinuous Galerkin method is employed to solve the structure-kinetics equation coupled with the conservation equations of mass and momentum. Depending on the normalized falling velocity $U^{*}$, which compares the time scale of structure formation and destruction, flow solutions are divided into three different regimes, which are attributed to an interplay of three competing factors: Brownian structure recovery, shear-induced structure breakdown, and the convection of microstructures. At small $U^{*}( \ll 1)$, where the Brownian structure recovery is predominant, the thixotropic effect is negligible and flow solutions are not too dissimilar to that of a Newtonian fluid. As $U^{*}$ increases, a remarkable structural gradient is observed and the structure profile around the settling sphere is determined by the balance of all three competing factors. For large enough $U^{*}(\gg 1)$, where the Brownian structure recovery becomes negligible, the balance between shear-induced structure breakdown and the convection plays a decisive role in determining flow profile. To quantify the interplay of three factors, the drag coefficient Cs of the sphere is investigated for ranges of $U^{*}$. With this framework, the effect of the destruction parameter, the confinement ratio, and a possible nonlinearity in the model-form on the non-homogeneous flow of a thixotropy fluid have been addressed.

Figures

Figures reproduced from arXiv: 1908.04993 by the authors.

Figure 1
Figure 1. The steady state viscosity ηss (4) of Moore thixotropy fluids in simple shear with the model parameters {η∞, ηstr, ka, kd} summarized in [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Schematic representation of a settling sphere inside a tube filled with a fluid. The boundary conditions for u = (ur, uz) are described on the frame of the sphere. The simulation domain for the axisymmetrically constrained case is shaded [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
Figure 3
Figure 3. Structure λ(x) at U ∗ = 0.1, 1.0, 100 at confinement ratio a/R = 0.25 U ∗ = (tc/a)U represents the ratio of thixotropic time scale to the flow strength. When U ∗ = 0.1, almost full structure is maintained and solution is close to Newtonian with viscosity η∞ + ηstr. As U ∗ increases, broken structures (blue region) start to appear from the vicinity of the sphere (r, z) = (a, 0). stabilization. In complex fluid flows … view at source ↗
Figures from the paper (11 more)
Figure 4
Figure 4. Figure 4: (a) λ(x) at U ∗ = 200. (b) Difference in structure solution between U ∗ = 200 and U ∗ = 100. Due to structure convection, the solution shape of λ is maintained qualitatively similar to that of U ∗ = 100 in Figure 3c. (c) Corresponding viscosity field η(x) = η∞ + ηstrλ(…
Figure 5
Figure 5. Figure 5: (a) Prediction of D for various U. The dashed line is Newtonian resistance DN with viscosity η∞ + ηstr. (b) The relation between Cs and U ∗ . The vertical line represents gross viscosity (normalized by η∞ + η0) that the sphere experiences by the viscosity field η(x). T…
Figure 6
Figure 6. Figure 6: Flow solution (p, ur, uz) at U ∗ = 200. The flow solution has fore-aft asymmetric due to inhomogeneous viscosity field around the sphere. r [m] z [m] 0 0.02 0.04 0.06 0.08 0.1 -0.08 -0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08 Structure 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0…
Figure 7
Figure 7. Figure 7: The shape of λ(x)-solution with respect to kd at U ∗ = 50. kd determines the equilibrium between the shear-induced breakdown and the structure convection for large U ∗ values. As kd increases, the fully broken structure (blue region) around the sphere expands to far fi…
Figure 8
Figure 8. Figure 8: The effect of the destruction parameter kd on the resistance. As kd increases, fully broken region expands around the sphere and hence ηe decreases. A finite value of kd distinguishes Moore thixotropy model from Generalized Newtonian model for U ∗ 1. The numerical sche…
Figure 9
Figure 9. Figure 9: The effect of the structural viscosity ηstr on (a) D-U curve and corresponding (b) Cs-U ∗ . The increase in ηstr shifts the D-U curve upward, whereas D-U remains relatively same because of the normalization factor (η∞ +ηstr) in the definition of Cs. In (a), it is shown…
Figure 10
Figure 10. Figure 10: Solutions of structure λ for different confinement ratio a/R at fixed U ∗ = 50. As a/R increases, the balance between shear-break and the structure convection is achieved with more broken structures in the vicinity of sphere. When a/R = 0.5, the wall interaction start…
Figure 11
Figure 11. Figure 11: The variation of Cs-U ∗ curve at different confinement ratio (a/R). The effect of confinement is negligible at small U ∗ At larger a/R, Cs drops much faster to lower plateau as U ∗ increases. Such effect is not confined to the terminal regime but greatly changes the s…
Figure 12
Figure 12. Figure 12: Steady shear viscosity ηss of nonlinear thixotropic model considered in Section 5. The kd2 in structure￾kinetics Eq. (32) is set as 1.0 [s], while the remaining model parameters are as in [PITH_FULL_IMAGE:figures/full_fig_p018_12.png]
Figure 13
Figure 13. Figure 13: The effect of the modified viscosity function (31) on the (a) D-U curve and (b) Cs-U ∗ curve is plotted. The nonlinearity implemented in the viscosity function (31) is still governed by the balance between structure breakdown and convection at large U ∗ . 10−5 10−4 10…
Figure 14
Figure 14. Figure 14: The resistance prediction for the nonlinear structure-kinetics equation (32). When the structure is more sensitive to applied shear rate than a linear scale, shear-induced breakdown effect dominates the Brownian recovery and structure convection as U ∗ increases. Ther…

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

83 extracted references · 80 canonical work pages

  1. [1]

    Mewis and N

    J. Mewis and N. J. Wagner. Colloidal Suspension Rheology, chapter Thixotropy, pages 228–251. Cambridge Series in Chemical Engineering. Cambridge University Press, 2011

  2. [2]

    R. G. Larson and Y. Wei. A review of thixotropy and its rheological modeling. Journal of Rheology, 63:477–501, 2019

  3. [3]

    Dullaert and J

    K. Dullaert and J. Mewis. A structural kinetics model for thixotropy. Journal of Non-Newtonian Fluid Mechanics, 139:21–30, 2006

  4. [4]

    Engmann and A

    J. Engmann and A. S. Burbidge. Fluid mechanics of eating, swallowing and digestion - overview and perspectives. Food & Function, 4:443–447, 2013

  5. [5]

    Quemada and R

    D. Quemada and R. Droz. Blood viscoelasticity and thixotropy from stress formation and relaxation measurements: a unified model. Biorheology, 20:635–651, 1983

  6. [6]

    R. G. de Krester and D. V. Boger. A structural model for the time-dependent recovery of mineral suspensions. Rheologica Acta, 40:582–590, 2001

  7. [7]

    Peptide-Based Physical Gels Endowed with Thixotropic Behaviour. N. zanna and c. tomasini. Gels, 3:39, 2017

  8. [8]

    Mortazavi-Manesh and J

    S. Mortazavi-Manesh and J. M. Shaw. Thixotropic rheological behavior of maya crude oil. Energy & Fuels, 28:972–979, 2014

Show all 83 references
  1. [9]

    Armelin, M

    E. Armelin, M. Mart´ ı, E. Rud´ e, J. Labanda, J. Llorens, and C. Alem´ an. A simple model to describe the thixotropic behavior of paints. Progress in Organic Coatings, 57(3):229–235, 2006

  2. [10]

    H. A. Barnes. Thixotropy—a review. Journal of Non-Newtonian Fluid Mechanics , 70(1–2):1–33, 1997

  3. [11]

    Mewis and N

    J. Mewis and N. J. Wagner. Thixotropy. Advances in Colloid and Interface Science , 147– 148:214–227, 2009

  4. [12]

    C. F. Goodeve. A general theory of thixotropy and viscosity. Transactions of Faraday Society, 35:342–358, 1939

  5. [13]

    F. Moore. The rheology of ceramic slips and bodies. Transactions and journal of British Ceramic Society, 58:470–494, 1959

  6. [14]

    Stickel, R

    J. Stickel, R. J. Phillips, and R. L Powell. A constitutive model for microstructure and total stress in particulate suspensions. Journal of Rheology, 50:379, 2006

  7. [15]

    J. D. Goddard. Dissipative materials as models of thixotropy and plasticity. Journal of Non-Newtonian Fluid Mechanics , 14:141–160, 1984

  8. [16]

    P. D. Patel and W. B. Russel. A mean field theory for the rheology of phase separated or flocculated dispersions. Colloids and Surfaces , 31:355–383, 1988

  9. [17]

    A. A. Potanin. On the mechanism of aggregation in the shear flow of suspensions. Journal of Colloid and Interface Science , 145:140–157, 1991. 24

  10. [18]

    D. S. Dickey and J. B. Fasano. How geometry and viscosity influence mixing. Chemical Engineering, 111:42–46, 2004

  11. [19]

    A. B. Metzner and R. E. Otto. Agitation of nonNewtonian fluids. AIChE Journal, 3:3–10, 1957

  12. [20]

    J. E. L´ opez-Aguilar, M. F. Webster, H. R. Tamaddon-Jahromi, and O. Manero. A comparative numerical study of time-dependent structured fluids in complex flows. Rheologica Acta, 55:197– 214, 2016

  13. [21]

    J. E. L´ opez-Aguilar, M. F. Webster, H. R. Tamaddon-Jahromi, and O. Manero. Numerical modelling of thixotropic and viscoelastoplastic materials in complex flows. Rheologica Acta, 54:307–325, 2014

  14. [22]

    J. E. L´ opez-Aguilar, M. F. Webster, H. R. Tamaddon-Jahromi, and O. Manero. High-weissenberg predictions for micellar fluids in contraction–expansion flows. Journal of Non-Newtonian Fluid Mechanics, 222:190–208, 2015

  15. [23]

    J. E. L´ opez-Aguilar, M. F. Webster, H. R. Tamaddon-Jahromi, and O. Manero. A new constitutive model for worm-like micellar systems – numerical simulation of confined contraction– expansion flows. Journal of Non-Newtonian Fluid Mechanics , 204:7–21, 2014

  16. [24]

    P. Coussot. Yield stress fluid flows: A review of experimental data. Journal of Non-Newtonian Fluid Mechanics, 211:31–49, 2014

  17. [25]

    A. N. Beris, J. A. Tsamopoulos, R. C. Armstrong, and R.A. Brown. Creeping motion of a sphere through a Bingham plastic. Journal of Fluid Mechanics , 1588:219–244, 1985

  18. [26]

    Blackery and E

    J. Blackery and E. Mitsoulis. Creeping motion of a sphere in tubes filled with a Bingham plastic material. Journal of Non-Newtonian Fluid Mechanics , 70:59–77, 1997

  19. [27]

    Tripathi and R

    A. Tripathi and R. P. Chhabra. Drag on spheroidal particles in dilatant fluids. AIChE Journal, 41:728–731, 1995

  20. [28]

    S. Tian. Wall effect for spherical partical in confined shear-thickening fluids. Journal of Non-Newtonian Fluid Mechanics , 257:13–21, 2018

  21. [29]

    Gervang, A

    B. Gervang, A. R. Davies, and T. N. Phillips. On the simulation of viscoelastic flow past a sphere using spectral methods. Journal of Non-Newtonian Fluid Mechanics , 44:281–306, 1992

  22. [30]

    P. Y. Huang and J. Feng. Wall effects on the flow of viscoelastic fluids around a circular cylinder. Journal of Non-Newtonian Fluid Mechanics , 60:179–198, 1995

  23. [31]

    Ferroir, H

    T. Ferroir, H. Huynh, and X. Chateau P. Coussot. Motion of a solid object through a pasty (thixotropic) fluid. Physics of Fluids , 16(3):594–601, 2004

  24. [32]

    Maleki-Jirsaraei, S

    N. Maleki-Jirsaraei, S. Hassani, and S. Azizi. Settling of spherical objects through thixotropic fluids: A statistical approach. Modern Applied Science, 12:72–76, 2018

  25. [33]

    M. M. Gumulya, R. R. Horsley, and V. Pareek. Numerical simulations of the settling behavior of particles in thixotropic fluids. Physics of Fluids , 26, 2014. 25

  26. [34]

    M. M. M. Thant, M. T. M. Sallehud-Din, G. Hewitt, C. Hale, and J. Quarini. Mitigating flow assurance challenges in deepwater fields using active heating methods. Society of Petroleum Engineer, 2011

  27. [35]

    C. R. Huang and W. Fabisiak. Thixotropic parameters of whole human blood. Thrombosis Research,, 8:1–8, 1976

  28. [36]

    J. J. Derksen. Simulations of thixotropic liquids. Applied Mathematical Modeling, 35(4):1656– 1665, 2011

  29. [37]

    J. B. Freund, J. Kim, and R. H. Ewoldt. Field sensitivity of flow predictions to rheological parameters. Journal of Non-Newtonian Fluid Mechanics , 257, 2018

  30. [38]

    C. M. Rodkiewicz, editor. Arteries and Arterial Blood Flow: Biological and physiological aspects . CISM International Centre for Mechanical Sciences. Springer-Verlag Wien, 1st edition, 1983

  31. [39]

    A. Tehrani. Thixotropy in water-based drilling fluids. Annual Transactions of the nordic rheology society, 16:1–13, 2008

  32. [40]

    Happel and H

    J. Happel and H. Brenner. Low Reynolds number hydrodynamics. Prentice-Hall, London, 1965

  33. [41]

    Tabuteau, P

    H. Tabuteau, P. Coussot, and J. de Bruyn. Drag force on a sphere in steady motion through a yield-stress fluid. Journal of Rheology, 51(1):125–137, 2007

  34. [42]

    Arndt, W

    D. Arndt, W. Bangerth, D. Davydov, T. Heister, L. Heltai, M. Kronbichler, M. Maier, J. P. Pelteret, B. Turcksin, and D. Wells. The deal.II library, version 8.5. Journal of Numerical Mathematics, 2017

  35. [43]

    Bangerth, R

    W. Bangerth, R. Hartmann, and G. Kanschat. deal.II — a general purpose object oriented finite element library. ACM Trans. Math. Softw. , 33(4):24/1–24/7, 2007

  36. [44]

    Taylor and P

    C. Taylor and P. Hood. A numerical solution of the navier-stokes equations using the finite element technique. Computers & Fluids , 1:73–100, 1973

  37. [45]

    J. S. Hesthaven and T. Warburton. Nodal Discontinuous Galerkin Methods: Algorithms, Analysis, and applications. Texts in Applied Mathematics. Springer-Verlag New York, 2008

  38. [46]

    Saramito

    P. Saramito. Complex Fluids: Modeling and Algorithms , volume 79 of Math´ ematiques et Applications. Springer, 2016

  39. [47]

    Saad and M

    Y. Saad and M. H. Schultz. GMRES: A generalized minimal residual algorithm for solving nonsymmetric linear systems. SIAM Journal on Scientific Computing , 7:856–869, 1986

  40. [48]

    R. C. Mittal and. A. H. AL-Kurdi. An efficient method for constructing an ilu preconditioner for solving large sparse nonsymmetric linear systems by the gmres method. Computers & Mathematics with applications , 45:1757–1772, 2003

  41. [49]

    R. B. Bird, R. C. Armstrong, and O. Hassager. Dynamics of Polymeric Liquids, Vol. 1: Fluid mechanics. Wiley, 2nd edition, 1987

  42. [50]

    Fraggedakis, Y

    D. Fraggedakis, Y. Dimakopoulos, and J. Tsamopoulos. Yielding the yield-stress analysis: a study focused on the effects of elasticity on the settling of a single spherical particle in simple yield-stress fluids. Soft Matter, 12(24):5378–5401, 2016. 26

  43. [51]

    M. M. Cross. Rheology of non-newtonian fluids: A new flow equation for pseudoplastic systems. Journal of Colloid Science , 20:417–437, 1965

  44. [52]

    panta rei

    Howard A. Barnes. The yield stress—a review or “panta rei ”— everything flows? Journal of Non-Newtonian Fluid Mechanics , 81(1):133 – 178, 1999

  45. [53]

    J. Kim, P. K. Singh, J. B. Freund, and R. H. Ewoldt. Uncertainty propagation in simulation predictions of generalized newtonian fluid flows. Journal of Non-Newtonian Fluid Mechanics , 271:104138, 2019

  46. [54]

    Mitsoulis and J

    E. Mitsoulis and J. Tsamopoulos. Numerical simulations of complex yield-stress fluid flows. Rheologica Acta, 56:231–258, 2017

  47. [55]

    N. J. Balmforth, I. A. Frigaard, and G. Ovarlez. Yielding to stress: Recent developments in viscoplastic fluid mechanics. Annual Review of Fluid Mechanics , 46:121–146, 2014

  48. [56]

    H. A. Ardakani, E. Mitsoulis, and S. G. Hatzikiriakos. Thixotropic flow of toothpaste through extrusion dies. Journal of Non-Newtonian Fluid Mechanics , 166:1262–1271, 2011

  49. [57]

    A. N. Alexandrou, N. Constantinou, and G. Georgiou. Shear rejuvenation, aging and shear banding in yield stress fluids. Journal of Non-Newtonian Fluid Mechanics , 158:6–17, 2009

  50. [58]

    R. L. Thompson, L. U. R. Sica, and P. R. S. Mendes. The yield stress tensor. Journal of Non-Newtonian Fluid Mechanics , 261:211–219, 2018

  51. [59]

    everything flows?

    M. Dinkgreve, M. M. Denn, and D. Bonn. “everything flows?”: elastic effects on startup flows of yield-stress fluids. Rheologica Acta, 56(3):189–194, 2017

  52. [60]

    J. E. L´ opez-Aguilar, M. F. Webster, H. R. Tamaddon-Jahromi, and O. Manero. Predictions for circular contraction-expansion flows with viscoelastoplastic & thixotropic fluids. Journal of Non-Newtonian Fluid Mechanics , 261:188–210, 2018

  53. [61]

    Renardy and Y

    M. Renardy and Y. Renardy. Thixotropy in yield stress fluids as a limit of viscoelasticity. IMA Journal of Applied Mathematics , 3:522–537, 2016

  54. [62]

    S Stephanou and G

    P. S Stephanou and G. G. Georgiou. A nonequilibrium thermodynamics perspective of thixotropy. The Journal of Chemical Physics , 149:244902, 2018

  55. [63]

    S. F. Lin and R. S. Brodkey. Rheological properties of slurry fuels. Journal of Rheology , 29(2):147–175, 1985

  56. [64]

    K. L. Pinder. Time dependent rheology of the tetrahydrofuran-hydrogen sulphide gas hydrate slurry. The Canadian Journal of Chemical Engineering , 42:132–138, 1964

  57. [65]

    G. R. Burgos, A. N. Alexandrou, and V. Entov. Thixotropic rheology of semisolid metal suspensions. Journal of Materials Processing Technology, 110:164–176, 2001

  58. [66]

    J. B. Freund and R. H. Ewoldt. Quantitative rheological model selection: Good fits versus credible models using Bayesian inference. Journal of Rheology, 59:667–701, 2015

  59. [67]

    H. Jeffreys. Theory of Probability. Oxford University Press, 3rd edition, 1961

  60. [68]

    X. Yang, H. Huang, and X. Lu. Sedimentation of an oblate ellipsoid in narrow tubes. Physical Review E, 92:063009, 2015. 27

  61. [69]

    I. E. Kareva and V. L. Sennitskii. Motion of a circular cylinder in a vibrating liquid. Journal of Applied Mechanics and Technical Physics , 42:276–278, 2001

  62. [70]

    Agarwal and R

    N. Agarwal and R. P. Chhabra. Settling velocity of cubes in newtonian and power law liquids. Powder Technology, 178:17–21, 2007

  63. [71]

    Sarpkaya

    T. Sarpkaya. Forces on cylinders and spheres in a sinusoidally oscillating fluid. Journal of Applied Mechanics, 42:32–37, 1974

  64. [72]

    V. L. Sennitskii. Motion of a sphere in a vibrating liquid in the presence of a wall. Journal of Applied Mechanics and Technical Physics , 40:662–668, 1999

  65. [73]

    Zhang, C

    L. Zhang, C. Yang, and Z-S. Mao. Numerical simulation of a bubble rising in shear-thinning fluids. Journal of Non-Newtonian Fluid Mechanics , 165:555–567, 2010

  66. [74]

    W. C. Chin. Computational Rheology for Pipeline and Annular Flow: Non-Newtonian Flow Modeling for Drilling and Production, and Flow Assurance Methods in Subsea Pipeline Design . Elsevier Science, 2001

  67. [75]

    Ratulowski A

    Ahmed J. Ratulowski A. Hammami. Precipitation and Deposition of Asphaltenes in Production Systems: A Flow Assurance Overview , pages 617–660. Springer New York, New York, NY, 2007

  68. [76]

    Bonn and M

    D. Bonn and M. M. Denn. Yield stress fluid slowly yield to analysis. Science, 324:1401–1402, 2009

  69. [77]

    M. M. Denn and D. Bonn. Issues in the flow of yield-stress liquids. Rheologica Acta, 50(4):307– 315, 2011

  70. [78]

    P. R. S. Mendes. Thixotropic elasto-viscoplastic model for structured fluids. Soft Matter , 7(6):2471–2483, 2011

  71. [79]

    C. J. Roy. Review of code and solution verification procedures for computational simulation. Journal of Computational Physics , 205:131–156, 2005

  72. [80]

    Steinberg and P

    S. Steinberg and P. J. Roache. Symbolic manipulation and computational fluid dynamics. Journal of Computational Physics , 57:251–284, 1985

  73. [81]

    P. J. Roache. Code verification by the Method of Manufactured solutions. Journal of Fluids Engineering, 124:4–10, 2001

  74. [82]

    Babuska and S

    I. Babuska and S. Szabo. On the rates of convergence of the finite element method. International Journal for Numerical Method for Engineering , 18:323–341, 1982

  75. [83]

    Brenner and L

    S. Brenner and L. R. Scott. The mathematical theory of finite element method , volume 15 of Texts in Applied Mathematics . Springer-Verlag New York, 2002. 28

Pith tools

Reviewed August 14, 2026 · model on record in the stance chip above.