Shear History Research Articles

Effect of Particle Shape on Cyclic Shear Behavior of Granular Mixtures–Geogrid Interface

The cyclic shear stiffness and damping ratio of angular and round particle geogrid interfaces is of much concern in reinforcement structure seismic analysis. In this study, various component percentages of crushed limestone and spherical granular medium mixtures were used to investigate the role of particle regularity in static and cyclic direct shear tests. The test results revealed that an increase in the proportion of round particles decreased cyclic shear strength and volume change. The phenomenon of shear softening was observed with a high amplitude of shear displacement when the proportion of round particles was increased in the mixture. As the percentage of round particles increased, the maximum interface shear stiffness decreased significantly from, 39.69 to 28.28 MPa/m, but a reverse trend in the maximum damping ratio was observed, from 0.308 to 0.37. The effect of cyclic shear history and proportion of round particles on interface strength parameters was also analyzed. A linear regression model was fitted to the data for quantifying the relationship between the proportion of round particles and friction angle. The results suggest that different percentages of round and angular particles can produce varying degrees of particle interlock between aggregate and geogrid, influencing the macro-mechanical behavior of the reinforced soil interface.

Improving the rheological and thermal stability of water-based drilling fluids by incrementing xanthan gum concentration

Water-based drilling fluids (WBDF) are often used over oil-based drilling fluids due to economic reasons and environmental regulations. Bentonite-free WBDF is preferred to aid in the reduction of formation damage. In many cases, this WBDF is formulated with xanthan gum. The performance of drilling operations is mainly affected by the drilling fluid formulation. The complex interactions among polymer concentration, thermal, and shear histories influence the rheological behavior of drilling fluids. The present study aims to analyze the effects of xanthan gum concentration on the rheological behavior of water-based drilling fluids. The experimental results performed in rotational rheometers revealed a relationship between concentration, yield stress, and thixotropic phenomena. The increase in xanthan gum concentration not only enhances the stability of the drilling fluid, allowing for more prolonged process interruptions without risking the fluid degradation but also improves the thermal stability of the sample. These findings show that the concentration of xanthan gum improves water-based drilling fluids' rheological and thermal stability.

Capillary flow-MRI of micronized fat crystal dispersions: Effect of shear history on microstructure and flow

Micronized fat crystal (MFC) dispersions are a novel food ingredient enabling more efficient manufacturing of fat-based products as compared to established melt-cool processing. Yet, predicting rheological properties of MFC dispersions, remains a challenge. Here, we demonstrate how a capillary-flow Magnetic Resonance Imaging (MRI) platform provides quantitative measurements of local flow of MFC dispersions, inaccessible by global rheology. The measured 2D 1H MRI velocity maps unveiled a 5-fold velocity enhancement, and corresponding increase in wall slip, upon increasing the pre-shear time within 0–5 h, due to the 14 % increase in thickness of the crystalline nanoplatelets via recrystallization and aggregation of nanoplatelets. In the absence of pre-shearing, MFC dispersions exhibit an unsheared band at the walls of the capillary, likely arising from fouling and migration of thin nanoplatelets. In contrast to FCDs, flow cooperativity could not be observed for MFC dispersions due to the non-fractality of the fat crystal network. These results demonstrate that, by varying the pre-shear duration, the flow-microstructure properties of the MFC dispersions can be altered in a controlled manner. The approach presented here will allow for rapid assessment of shear-history dependence of flow properties of MFC dispersions under industrially relevant flow conditions.

The effect of cavity shape on critical high-temperature regions formation pattern and structural evolution difference in explosive particle bed

The occurrence of critical high-temperature regions within explosives is a crucial factor in initiating combustion and explosion. The primary causes of hot regions in cavity-containing explosives are dissipative processes occurring inside the explosive or at its interface, such as shear, friction, viscosity, plasticity, and heat transfer. Currently, there is limited research on the generation and dissipation mechanisms of critical high-temperature regions in cavity-containing explosives during impacts, based on the mesoscale analysis that describes particle motion. In this study, a model based on the discrete element method is employed allowing for an accurate analysis of the dynamic and thermodynamic processes among particles, which systematically considers the shear history between particles, elastoplastic collisions, and heat transfer between particles. The temporal evolution of particle temperature and dissipated work contours during the impact process of explosives with different cavity shapes is analyzed. Explosives with cavities undergo three stages during the impact process: the formation of the trapezoidal high-temperature region, cavity collapse, and dispersion of the particle bed, ultimately leading to the formation of two main critical high-temperature regions: near the cavity and near the wall. The temperature rise of hot particles near the wall can be roughly divided into two stages, and the temperature rise mechanisms are different. Initially, the temperature rise is primarily attributed to plastic dissipation of hot particles, and the same initial impact velocity results in the same temperature rise. During the cavity collapsing, continuous momentum transfer occurs between the hot particles near the wall and the particles in the high-temperature shear bands, deeply influencing the development of the high-temperature shear bands through the movement of the hot particles near the cavity. Therefore, the different collapse modes of hot particles near cavities of different shapes lead to differences in the later temperature evolution of the hot particles near the wall. The unique aggregation processes of hot particles near cavities of various shapes result in distinct high-temperature region morphologies: circular cavity exhibits approximate “——” shape, triangular cavity displays arch shape, and inverted triangular cavity presents “M” shape. Significantly, a new mechanism resulting from the interaction of two opposing “jet “flows for the formation of higher-temperature hot regions near the circular cavity has been discovered.

Interfacial rheology of cyclopentane hydrate formation: Insights into mechanical behavior and inhibitor efficiency

Hydrates are crystalline solids with an ice-like texture, which are formed when light hydrocarbon molecules and water combine to form a specific ordered structure. Hydrate formation begins at the water–hydrocarbon interface, which highlights the critical role that interfacial rheology plays in this process. Despite the significance of this interface in hydrate formation, a gap in research persists, particularly in employing shear rheology approaches. This study helps to fill this void by investigating the mechanical and flow properties of the interface, using a feature in a rotational rheometer, a “double wall ring cell,” for precise temperature control. Cyclopentane serves as the hydrate former, allowing experimentation under atmospheric pressure and varied temperatures. Protocols explore temperature and hydrocarbon concentrations, with emphasis on ice crystal involvement in hydrate formation initiation. Following complete saturation of the hydrocarbon/water interface by hydrates, interfacial elastic and viscous moduli are obtained through strain sweeps to assess hydrate film fragility and mechanical response. Additionally, the impact of aging time and shear type (static or dynamic) on hydrate stiffness is examined. Tests with thermodynamic inhibitors, such as sodium chloride and monoethylene glycol, demonstrate significant induction time extension. Furthermore, systematic changes in the shear rate are investigated to comprehensively understand their influence on hydrate film characteristics and properties under varying shear history conditions. This study reveals that increasing shear rate correlates with decreased viscosity of the hydrate film, indicative of non-Newtonian behavior. Overall, this research sheds light on the nuanced dynamics of the water–hydrocarbon interface in hydrate formation and mitigation.

Using crack width for shear, stiffness, and stirrup strain history predictions for reinforced concrete beams

Shear failures in reinforced concrete structures occur with little or no warning. Reinforced concrete members with shear cracks should be evaluated to ensure safety. Existing evaluation methods have large variability, require time-consuming modeling or expert opinion. This study uses machine learning to investigate correlations of crack width with shear loading, stiffness, and stirrup strain histories. Experimental literature enables the assembly of a database of rectangular reinforced concrete slender beams with crack width measurements for beams with shear reinforcement amounts smaller and larger than the minimum required by ACI 318-19. Measured data include crack widths from 122 beams, load–displacement relationship from 100 beams, and stirrup strains from 46 beams. Gaussian Process Regression is used to correlate crack width and geometric, material and design properties to shear loading, stiffness, and stirrup strain histories. Ten-fold cross validation training shows mean absolute percent errors of 18, 33 and 77% for shear, stiffness, and stirrup strain history predictions. The proposed algorithms can be used to accelerate the evaluation of in-service structures and can be updated upon availability of additional data.

The quest for down scale representativeness: how to exploit CFD to design a shear study for vaccines

In this work, we exploit computational fluid dynamics (CFD) to evaluate stirred tank reactor (STR) process engineer parameters (PEP) and design a scale-down system (SDS) to be representative of the formulation and filling process steps for an Aluminum adjuvanted vaccine drug product (DP). To study the shear history in the SDS we used the concept of number of passages, combined with an appropriate stirring speed down scale strategy comprising of either (i) tip speed equivalence, widely used as a scale-up criterion for a shear-sensitive product, or (ii) rotating shear, a shear metric introduced by Metz and Otto in 1957 but never used as scaling criterion. The outcome of the CFD simulations shows that the tip equivalence generates a worst-case SDS in terms of shear, whereas the rotating shear scaling approach could be used to design a more representative SDS. We monitored the trend over time for “In Vitro Relative Potency” as DP Critical Quality Attribute for both scaling approaches, which highlighted the crucial role of choosing the appropriate scaling-down approach to be representative of the manufacturing scale during process characterization studies.

Design and experimental study on rheological behavior and sealing performance of shear sensitive fluids to control lost circulation during drilling

Loss circulation is considered as a time-consuming, costly, and challenging issue while drilling or cementing jobs, which ought to be treated and resolved promptly. The choice of a treatment that quickly plugs the loss zone and helps to restore the circulation is critical. Cross-linkable polymer gels play a significant role in mitigating drilling fluid loss, but controlling the gelation time and pumpability are the main challenges of these gels. This research aims to evaluate a novel smart fluid that has high flexibility in design. The shear sensitive fluid (SSF) is an oil-based fluid containing a polymer, gelation agents, and multi-crosslinkers. After passing through the drilling bit, the SSF is crosslinked with time to produce a high strength gel. The designed shear sensitive fluid is one of the possible solutions for severe loss circulation.The overall purpose of this research was to scrutinize the gelation behavior and SSF performance as a smart lost circulation treatment, which was followed in two sections including experimental analysis and empirical modeling. The effect of various factors including the type of crosslinker, shear rate, emulsifier concentration, temperature, shear history, salinity, etc. on the performance of the formed gels was studied. Furthermore, the maximum sealing pressure of formed gels in the highly permeable porous medium and fractured core as well as the probability of formation damage was evaluated.In order to determine the correlations required to predict the ultimate gelation time of SSF, the response surface methodology was utilized according to the central composite design. The considerable values of correlation coefficients (R2 = 0.91) prove the validity of estimated models for the fit enough responses with the experimental data. For the designed SSFs, depending on the operating conditions, the appropriate gelation time can be adjusted by emulsifier concentration and shear rate values. Also, the minimum gelation time and the highest crosslinking rate occur approximately at the shear rate of 45,000 1/s. At high shear rates, the effect of temperature on the functionality of the formed gels decreases, which is due to the high rate of crosslinking. Based on dynamic sealing pressure tests, the SSFs have a high potential in mitigation of lost circulation during drilling. The maximum sealing pressure was measured above 1000 psi in highly permeable porous medium and up to 600 psi in fractured core, which indicate the high strength of the formed gels against drilling fluid pressure. The designed SSFs could be easily removed from reservoir by 15 vol% hydrochloric acid, indicating the non-damaging properties of the formed gels.

Reassessing the timing of high-strain deformation in the Strangways Metamorphic Complex, Central Australia, by in situ mica Rb–Sr and titanite U–Pb geochronology

Dating the timing of deformation within shear zones is critical to quantifying orogenic processes and developing time-resolved regional tectonic frameworks. Such work requires the integration of detailed microstructural analysis with in situ geochronology to quantify when deformation mechanisms were active at the micro-scale. The Proterozoic, granulite-facies Strangways Metamorphic Complex was exhumed during the Devonian to Carboniferous intracontinental Alice Springs Orogeny. New microstructural observations, quartz c -axis orientation analyses, mica chemistry, Ti-in-biotite thermometry, in situ mica Rb–Sr and titanite U–Pb geochronology outline a detailed history of ductile shearing across the complex. Movement along the north boundary shear zone of Strangways Metamorphic Complex appears to have initiated c. 382 Ma, preceding peak metamorphism in the area during the Alice Springs Orogeny. Widespread reverse-sense ductile shearing occurred within the Strangways Metamorphic Complex between c. 365 and 355 Ma, and correlates with rapid cooling of the region. Late-stage ductile deformation is recorded at c. 335 Ma, likely reflecting the terminal exhumation of the Strangways Metamorphic Complex. Finally, the new in situ muscovite and biotite Rb–Sr data collected herein permit comparison with previous two-point mica Rb–Sr isochrons and 40 Ar– 39 Ar dates from the same specimens. In the rocks analysed, the biotite Rb–Sr system returned dates similar to the previous 40 Ar– 39 Ar white mica dates, perhaps indicating a similar effective closure temperature. Supplementary material: Test results and previous geochronology data from the Alice Springs Orogeny are available in tabular form at https://osf.io/yjp24/?view_only=0bf5bec9f5c94a1aa4fb413320ec24e8

Growth and static stability of bubble clouds in yield stress fluids

This study explores the growth and static stability of bubble clouds in yield-stress fluids using an experimental approach. Carbopol gels with varying concentrations and initial gas contents as well as Laponite gels are used as model yield stress fluids in our experiments. A vacuum system is exploited to generate the bubbles and control their growth in the gels. The focus of this study is on determining the maximum gas concentration which could be held trapped in the system and the critical yield number, i.e. the ratio of the yield stress to the buoyancy stress at the onset of motion. Our findings demonstrate the effect of the bubbles proximity as well as the gel structure and rheology on both the maximum gas concentration and critical yield number. Our results confirm that for higher gas fractions, the critical yield number is larger. Also, they show that the size and degree of elongation of the bubbles at the onset of motion are controlled by their proximity as well as the gel rheology. Moreover, our results reveal two different scenarios for the bubble release depending on the uniformity of the structure of the gel. In the case of low concentration Carbopol gels, characterized by uniform structures, quasi mono-dispersed bubble suspensions are formed. At a pretty high gas concentration, this might lead to a bubble cloud burst upon static instability onset. Conversely, in the case of high concentration Carbopol gels or Laponite gels, the polydisperse bubble suspensions emerge and the bubble release occurs gradually rather than suddenly. It can be associated with the heterogeneous structure of these gels stemming from their significant shear history dependence.

Shear Histories Alter Local Shear Effects on Thrombus Nucleation and Growth.

Our goal was to determine the impact of physiological and pathological shear histories on platelet nucleation and thrombus growth at various local shear rates. We designed and characterized a microfluidic device capable of subjecting platelets to shear histories reaching as high as 6700s in a single passage. Time-lapse videos of platelets and thrombi are captured using fluorescence microscopy. Thrombi are tracked, and the degree of thrombosis is evaluated through surface coverage, platelet nucleation maps, and ensemble-averaged aggregate areas and intensities. Surface coverage rates were the lowest when platelets deposited at high shear rates following a pathological shear history and were highest at low shear rates following a pathological shear history. Early aggregate area growth rates were significantly larger for thrombi developing at high shear following physiological shear history than at high shear following a pathological shear history. Aggregate vertical growth was restricted when depositing at low shear following a pathological shear history. In contrast, thrombi grew faster vertically following physiological shear histories. These results show that physiological shear histories pose thrombotic risks via volumetric growth, and pathological shear histories drastically promote nucleation. These findings may inform region-based geometries for biomedical devices and refine thrombosis simulations.

Scaling laws for near-wall flows of thixo-elasto-viscoplastic fluids in a millifluidic channel

Thixo-elasto-viscoplastic (TEVP) fluids are very complex fluids. In addition to elasticity and viscoplasticity, they exhibit thixotropy, i.e., time-dependent rheology due to breakdown and recovery of internal structures at different length- and timescales. General and consistent methods for a priori flow prediction of TEVP fluids based on rheological characteristics are yet to be developed. We report a combined study of the rheology and flow of 18 samples of different TEVP fluids (three yogurts and three concentrations of Laponite and Carbopol, respectively, in water in both the unstirred and a stirred state). The rheology is determined both with standard protocols and with an ex situ protocol aiming at reproducing the shear history of the fluid in the flow. Micrometer resolution flow measurements in a millimeter scale rectangular duct are performed with Doppler Optical Coherence Tomography (D-OCT). As expected, the results show the existence of a plug flow region for samples with sufficiently high yield stress. At low flow rates, the plug extends almost all the way to the wall and the extent of the plug decreases not only with increased flow rate but also with increased thixotropy. The ex situ rheology protocol enables estimation of the shear rate and shear stress close to the wall, making it possible to identify two scaling laws that relates four different non-dimensional groups quantifying the key properties wall-shear stress and slip velocity. The scaling laws are suggested as an ansatz for a priori prediction of the near-wall flow of TEVP fluids based on shear flow-curves obtained with a rheometer.

Calibration of Thixotropic and Viscoelastic Shear-Thinning Fluids Using Pipe Rheometer Measurements

Some non-Newtonian fluids have time-dependent rheological properties like a shear stress that depends on the shear history or a stress overshoot that is a function of the resting time, when fluid movement is started. The rheological properties of such complex fluids may not stay constant while they are used in an industrial process, and it is therefore desirable to measure these properties frequently and with a simple and robust device like a pipe rheometer. This paper investigated how the time-dependent rheological properties of a thixotropic and viscoelastic shear-thinning fluid can be extracted from differential pressure measurements obtained at different flowrates along a circular pipe section. The method consists in modeling the flow of a thixotropic version of a Quemada fluid and solving the inverse problem in order to find the model parameters using the measurements made in steady-state conditions. Also, a Maxwell linear viscoelastic model was used to reproduce the stress overshoot observed when starting circulation after a resting period. The pipe rheometer was designed to have the proper features necessary to exhibit the thixotropic and viscoelastic effects that were needed to calibrate the rheological model parameters. The accuracy of rheological measurements depends on understanding the effects that can influence the observations and on a proper design that takes advantage of these side effects instead of attempting to eliminate them.

Fabric-based jamming phase diagram for frictional granular materials.

A jamming phase diagram maps the phase states of granular materials to their intensive properties such as shear stress and density (or packing fraction). We investigate how different phases in a jamming phase diagram of granular materials are related to their fabric structure via three-dimensional discrete element method simulations. Constant-volume quasi-static simple shear tests ensuring uniform shear strain field are conducted on bi-disperse spherical frictional particles. Specimens with different initial solid fractions are sheared until reaching steady state at a large shear strain (200%). The jamming threshold in terms of stress, non-rattler fraction, and coordination numbers (Z's) of different contact networks is discussed. The evolution of fabric anisotropy (F) of each contact network during shearing is also examined. By plotting the fabric data in the F-Z space, a unique critical fabric surface (CFS) becomes apparent across all specimens, irrespective of their initial phase states. Through the correlation of this CFS with fabric signals corresponding to jamming transitions, we introduce a novel jamming phase diagram in the fabric F-Z space, offering a convenient approach to distinguish the various phases of granular materials solely through the direct observation of geometrical arrangements of particles. This jamming phase diagram underscores the importance of the microstructure underlying the conventional jamming phenomenon and introduces a novel standpoint for interpreting the phase transitions of granular materials that have been exposed to processes such as compaction, shearing, and other complex loading histories.

A shear history model for capturing the liquefaction resistance of sands at various cyclic stress ratios

Various constitutive formulations have been developed over the years to reproduce the cyclic resistance of sands. A common challenge for existing models is the accurate simulation of the cyclic strength of sands for a wide range of initial conditions and different cyclic stress levels when adopting a single calibration. Many liquefaction models tend to overpredict the resistance of the soil under large-amplitude loading, while underestimating the strength at low-amplitude cyclic shearing. This manifests itself in slopes of simulated cyclic resistance ratio curves (CRR-curves) which are steeper than experimental studies indicate. This paper provides a discussion on the effects of large-amplitude and low-amplitude cyclic shearing on a granular material based on micromechanical and experimental investigations presented in the literature. A constitutive model with a shear-history threshold is proposed, which accounts for a shift of the apparent angle of phase transformation under cyclic loading. In addition, a novel expression for a deviatoric fabric tensor is introduced to describe the evolution of shear-induced fabric anisotropy while a soil is dilating and contracting. Combining these two features in one formulation within the bounding surface plasticity framework enables an accurate prediction of cyclic strength of sands under a wide range of cyclic stress ratios.

Mechanisms of thixotropy in cement suspensions considering influences from shear history and hydration

AbstractThe rheological properties of fresh concrete are a direct function of the interaction behaviour of the granular inventory of the concrete (i.e., gravel, sand and cement) and especially of the colloidal fractions of cement. Under low shear stresses, agglomeration of colloidal particles is observed, while at high shear stresses, dispersion of these agglomerates occurs. Besides the agglomeration state, the formation of shear banding, zones with concentrated shear flow, is another controlling mechanism of the flow behaviour of cement suspensions. Rheological creep tests in this study are focused on investigating the influence of shear history and hydration process on thixotropy of cement suspension. In this paper, the meaning of the word thixotropy is slightly extended to additionally encompass rheological aging and hydration effects. Selected samples were analyzed by coupling a rheometer to synchrotron X‐ray tomography to gain insight into the shear‐induced microstructural changes during shear start‐up tests. The observations show heterogeneities in the velocity profile in the shear gap and the development of shear banding.

Effect of Shear History on Solid-Liquid Transition of Particulate Gel Fuels.

Investigating the structural evolution of particulate gels is a very challenging task due to their vulnerability and true flow characteristics. In this work, deeper insight into the rheological properties of gel fuels filled with fumed silica (FS) and aluminum microparticles (Al MPs) was gained by changing shear procedures. Firstly, the flow curves were found to no longer follow the monotonic power law and exhibited subtle thixotropic responses. As the shear rate increased, the gel structure underwent a transition from local shear to bulk shear in the nonlinear region after yielding. This finding reveals the prevalence of nonideal local shear in industry. Secondly, the time-dependent rheological responses demonstrated that the strength spectrum of gel fuels depends on the applied shear rate, with stress relaxation more easily observed at lower shear rates. Those results involved the structural disruption, recovery, and equilibrium of particulate gels from two scales of shear rate and shear time.

The effect of thixotropy on the yield transition in reversible, colloidal gels.

Thixotropic yield-stress fluids (TYSFs) are a unique class of materials whose properties are affected by both shear rate and shear history. When sheared, these materials undergo a transition from an elastic solid to a viscoelastic fluid, which is accompanied by a structural transition that slowly recovers upon the cessation of shear. The strong interdependence between structure, dynamics, and rheological properties in TYSFs make it challenging to identify the fundamental physics controlling these phenomena. In this study, we vary the ionic strength of a suspension of cellulose nanocrystals (CNC) to generate model TYSFs with tunable moduli and thixotropic kinetics. We use a novel rheological protocol-serial creep divergence-to identify the physics underlying the yield transition and recovery of CNC gels. Our protocol identifies a critical transition that bifurcates the solid-like and fluid-like regimes of the gels to precisely determine the yield stress of these materials even in the presence of thixotropic effects. Additionally, the thixotropic kinetics collapse onto a single master curve, which we fit to a transient solution to a coupled diffusion-aggregation model. Our work thereby identifies the underlying physicochemical mechanisms driving yielding and thixotropic recovery in attractive colloidal gels.

Experimental study on sand anisotropy using hollow cylinder apparatus

This study investigated sand anisotropy experimentally using a hollow cylinder apparatus. The effect of the initial anisotropy on the shear behavior of sand was illustrated by conducting experiments on specimens with bedding planes and systematically varying the density, principal stress direction, and intermediate principal stress. The change in induced anisotropy during shearing was experimentally captured by re-shearing the specimens subjected to prior shear history. The experimental results revealed the following: (a) Anisotropy in sand, whether initial anisotropy developing during specimen preparation or induced anisotropy developing due to shear history, causes pseudo-density changes in the mechanical behavior, in which sand of the same density behaves as if it has a different density depending on the direction of shear. (b) The changes in induced anisotropy, due to shearing in the same direction as that of the prior shear, make the soil behave similarly to dense sand, whereas shearing in a direction perpendicular to the prior shear makes the soil behave similarly to loose sand. (c) The larger the prior shear, the more pronounced the pseudo-density changes that appear in the subsequent behavior. Moreover, the significance of induced anisotropy in liquefaction and compaction phenomena was experimentally demonstrated through single and double swing cyclic shear tests. The results obtained from the study will be useful for validating models that incorporate induced anisotropy.

Numerical simulations of the flow of a kerosene gel: Effects of thixotropy and shear-thinning

The ability of a gel to act like a solid-like material at rest and flow like a liquid when sheared can be very useful in propulsion system. Numerical simulation of the flow of gel fuels can be used as a reference to assist experimental studies and applications of these materials. Non-linear rheological effects such as shear thinning, yield stress, thixotropy and viscoelasticity can create difficulties in the formulation and in the numerical investigations. This paper uses a thixotropic shear-thinning constitutive relationship while using a second-order kinetic equation for the structural parameter, where the Carreau–Yasuda model is used for a 5% organic kerosene gel. We study the simple shear flow to verify the accuracy of the numerical method, and the impact of the constitutive parameters on the apparent viscosity as a function of shear rate. To look at the thixotropic flow in more complex flows, we initially study the pipe flow of an organic kerosene gel for different pumping conditions. After performing a parametric study, we find that the thixotropy of the gel strongly affects the shear history, that is, the nonuniform aging distribution. The destruction of the microstructure can be accelerated by adjusting the flow intensity and the model parameters, but it seems that it is difficult to arrive at the equilibrium state within the time scale of the propulsion system; this poses a challenge to the design of the system.