Yield Stress Parameters Research Articles

The effect of peristalsis on dispersion in Casson fluid flow

The present study examines the peristaltic flow of a non-Newtonian (Casson) fluid and solute transport through a flexible tube. Using the long-wavelength approximation, an analytical solution for the Casson fluid velocity is obtained in the axial and radial directions. Then, a numerical solution to the solute concentration is computed using the standard Galerkin finite element method (FEM) for the case of solutal convection-diffusion and the Discontinuous Galerkin FEM for the pure convection case. Graphical results are presented for the axial and local solute concentrations, and the influence of peristaltic wave amplitude, volumetric flow rate, modified Péclet number, time, yield stress, and pertinent initial condition parameters were investigated.

Correction to: A metamodel for confined yield stress flows and parameters’ estimation

Correction to: A metamodel for confined yield stress flows and parameters’ estimation

Analiza elastično-plastičnog naprezanja skupljajućih debelih FGM cilindara

This paper addresses the stress analysis of shrink-fitted thick-walled cylinders made of functionally graded material (FGM). Analytical solutions are provided for the elastic-plastic behavior of shrink-fitted axisymmetric thick-walled FGM cylinders based on the linear plane elasticity theory and plasticity laws. Due to the material's functional gradation, mechanical characteristics like Young's modulus, yield stress, and plastic parameters are controlled by a power function along the wall thickness. Considering a plane strain case, elastic-perfectly plastic model and Von Mises yield criterion; theoretical solutions are obtained for both elastic and plastic phases. The radial, hoop, axial, and equivalent Von Mises stresses are obtained for up to 25%, 50%, and 75% of cylinder plasticization for the elastic and plastic zones. Stresses are given in terms of interference and geometrical and mechanical parameters of the assembly. In addition, the interferences to start plastic deformation and the full plastic collapse of the cylinder are discussed. Moreover, the effect of the gradient index on the contact pressure and both the start of yield and plastic collapse pressures are conducted. The analytical results found in the current research are compared with the numerical solutions carried out by Ansys Workbench. Both results show a good agreement.

Effect of Using Nano-TiO2 on the Rheological Properties of Cementitious Systems

Self-cleaning concrete (SCC) was developed that can reduce air pollution by utilizing its photocatalytic property. Due to this feature, polluting materials are broken down into H2O and CO2, which are completely harmless, without the need for any additional carrier gas. For this purpose, it was emphasized that semiconductor oxides with photocatalytic properties such as TiO2, ZnO, CdSe and WO3 are used in the production of SCC. Compared to other oxides, it was determined that nano-TiO2 is more commonly preferred. However, it was emphasized that the use of nano-TiO2 due to the high surface area/volume ratio increases the water requirement and the risk of agglomeration of cementitious systems. This situation directly affects the rheological properties of SCC. In this study, the effects of nano-TiO2 utilization ratio change on the rheological properties of cementitious systems were investigated. For this purpose, a total of 4 mixtures were prepared by substituting nano-TiO2 with 28 nm at a rate of 0, 0.5, 1 and 1.5% by weight of cement. The rheological properties of the prepared mixtures were evaluated according to the dynamic yield stress (DYS), apparent viscosity (AV) and structural build-up (Athix) parameters. It was understood that the DYS, AV and Athix values of the mixtures increased with the increase of nano-TiO2 utilization ratio.

Rheological Properties and Kinetics of Gelation of Binary Polymers between Xanthan Gum and Locust Bean Gum.

The synergistic interaction and gelling kinetics between xanthan gum (XG) and locust bean gum (LBG) at different mass ratios (XG/LBG 9:1, 7:3, 5:5, 3:7, 1:9) were investigated using a rheometer. The results showed that the mixtures of XG and LBG induced gel formation, and the strongest gel structure was found for the mixture of XG/LBG 3:7 according to the yield stress, storage modulus (G'), and power law parameters. Temperature ramp studies indicated that heating destroyed the gels at 55~60 °C, while cooling induced the sol-gel transition at around 52 °C for all mixtures. Structure developing rate (SDR) curves showed that XG/LBG 3:7 exhibited the highest SDR during the cooling ramp among all the samples. Non-isothermal kinetic analysis demonstrated that the gelation process of XG/LBG mixtures during cooling included two steps: a high-temperature region (55~39 °C) needing higher activation energy (Ea, 111.97 to 199.20 kJ/mol for different mixtures) and a low-temperature region (39~20 °C) needing lower Ea (74.33 to 85.31 kJ/mol), which indicated higher energy barriers to overcome at the initial stage of gel formation. The lowest Ea of 74.33 kJ/mol was found for XG/LBG 3:7 in the low-temperature region. Scanning electron microscopy (SEM) showed that the gel of XG/LBG 3:7 presented the densest entanglements. These results indicated the strongest synergism interaction occurred in XG/LBG 3:7 to form gel network structures. This study will help promote the application of XG-LBG blends to design novel food structures.

Rheological Properties of Carbon Nanotube Infused Cementitious Composites with Various Amounts of CNT

The addition of carbon nanotubes (CNTs), which are hydrophobic materials, significantly influences the rheology of cementitious materials but requires important mix modifications in order to provide proper flowability for further use. This paper investigates the influence of various dosages of carbon nanotubes (0.05 wt.%, 0.1 wt.%, 0.2 wt.%, 0.5 wt.%, and 1 wt.%) on the flowability, rheological parameters, air content, and volume density of cement mortars. The results show an increase in the yield stress parameter with an increment in CNT dosage up to the threshold of 0.5 wt.% for mixes with an increased amount of cement. For standard proportions, it was on a stable level for all mixes except for 0.2 wt.%. The plastic viscosity parameter also increased with the CNT dosage; mixes with standard proportions of components were not higher than the reference, and mixes with an increased amount of cement were lower than the reference for dosages up to 0.5 wt.% of CNT. The addition of a superplasticizer and modifications of the ratio of the components were employed to achieve proper flowability and measure the rheological parameters. The presented results show that regardless of the negative influence of carbon nanotubes on the properties of fresh mortar, it is possible to achieve a stable flow and workability using simple modifications of the composition.

The protective performance of rubber pads for penetration fuze

To ensure the reliable functioning of hard target-penetration fuze on the battlefield, this study focuses on research related to fuze protective pads. The main factors causing fuze functional failure are summarized, and a simplified model of projectile penetration into target plates is established. The design conditions for the yield stress parameter of the fuze casing material are derived based on stress wave propagation theory. Modal analysis of the projectile is conducted using dynamic simulation software ANSYS to determine its vibration modes and low-pass filtering frequency. Static compression experiments are performed on different rubber materials (nitrile rubber, fluorine rubber, silicone rubber, and natural rubber) to obtain stress–strain curves and constitutive model parameters. Marshall hammer tests were carried out on rubber pads of different materials and thicknesses, confirming the validity of the simulation results and the feasibility of rubber filtering. The study indicates that when using a 2 mm thick rubber pad for protection, natural rubber provides the best protection. When using a 6 mm thick rubber pad, nitrile rubber shows the best protective performance. Under a 13-tooth tooling impact load, the best protection is achieved using a 2 mm thick natural rubber pad. When using a 6 mm thick pad, silicone rubber provides the best protection. Under a 15-tooth tooling impact load, fluorine rubber provides the best protection when using a 2 mm thick pad, while silicone rubber offers the best protection when using a 6 mm thick pad. Under a 17-tooth tooling impact load, natural rubber offers the best protection when using a 2 mm thick pad, and fluorine rubber demonstrates the best protection when using a 6 mm thick pad. The obtained research results provide a reference for protective methods of hard target-penetration fuze.

Insights into the role of tooling characteristics on compressibility evolution in non-flat faced tablets

The robustness of tablet manufacturability largely depends on compressibility behavior of a powder. The compressibility assessment is traditionally conducted on cylindrical flat-faced compacts in contrast to the fact that marketed tablets are majorly produced using non-flat faced or shaped toolings. The present work demonstrates the feasibility of quantifying average compressibility on shaped toolings through a proof-of-concept study by investigating the central band portion and the entire volume of the tablet, which led to several notable findings. Firstly, the yield stress (deformability) was found independent of type of tooling for a given powder in the in-die condition, but for the same tooling it conversely spanned over a wide range in the out-die condition due to characteristic elastic recovery. Secondly, the yield stress parameter correlated with the change in band volume of the shaped tablet with applied compaction pressure, thereby establishing an orthogonal approach to assess compressibility on non-flat faced toolings. The study emphasizes that tooling characteristics may affect compressibility and tablet robustness of a same powder, which should be practiced cautiously in drug product manufacturing.

Thermal radiation effect on Non-Newtonian Casson fluid through a porous material over a magnetic field with buoyancy

The magnetohydrodynamic (MHD) chemically reactive of Casson non-Newtonian nanofluid flow on a two-dimensional incompressible steady from stretched sheet in a porous quiescent medium with buoyancy effect is investigated numerically. Additional effects included in the originality of the model are the applied magnetic field and solar radiation effect. The Chebyshev collocation method (CCM) was used to solve the ordinary differential equations (ODEs) with MATHEMATICA 11.3 software. The present tables and graphs show the performance of fluid physical quantities, momentum flow, energy distribution, nanoparticle concentration, and velocity for various values of applicable dimensionless numbers. The numerical outcomes demonstrate the effect of different physical parameters of the fluid, and it was observed that the velocity profile increased as the thermal and mass Grashof number increased due to an increase in buoyant force caused by heat transferred from the vertical plate to the fluid but decreased as the Casson parameter increased due to a decrease in its yield stress, porosity, and magnetic parameter. Also Analyses reveal that the thermal profile reduce with an increase in variable thermal conductivity parameter. This study will be of considerable economic value to marine engineers, mechanical engineers, physicists, chemical engineers, and others since its application will help them improve their operations.

Effects of sediment fractions on slump-flow parameters of fine- and coarse-sediment suspensions

• Slump-flow parameters (slump and spread) of fine- and coarse-sediment suspensions are measured using a mini-slump cone. • Effects of fine- and coarse-sediment fractions on the slump-flow parameters are analyzed and empirically formulated by power-law and exponential relations, respectively. • The single- and double-layer models of Roussel and Coussot [22] and Pierre et al. [21], respectively are generalized for a conical-shaped mould in the range of 0 < α ≤ 1 . • The dimensionless slump and spread of fine- and coarse-sediment suspensions are strongly correlated and their empirical relation was compared to the theoretical relations. • The slump-flow parameters and Bingham yield stress exhibit good correlations in both theoretical and empirical analyses, indicating that the slump-flow test may be used to indirectly evaluate the rheology of sediment suspensions. Slump-flow tests on concentrated fine-sediment suspensions (mixtures of clay-silt-water) and coarse-sediment suspensions (mixtures of coarse sediments and a specified fine-sediment suspension) were performed to investigate the effects of sediment fractions on the slump-flow parameters (slump and spread). The slump and spread of fine- and coarse-sediment suspensions decrease with an increase in the sediment fractions, and their empirical equations were proposed. Both experimental and theoretical results show that the slump and spread of sediment suspensions are strongly correlated. Theoretical relations of the Bingham yield stress and slump-flow parameters were also presented for comparison. The slump-flow parameters exhibit a strong correlation with the rheological parameters measured using a conventional rheometer, indicating that the rheological parameters of the tested sample could be indirectly evaluated by a simple slump-flow test.

SPH simulations of thixo-viscoplastic fluid flow past a cylinder

Thixotropic materials are complex fluids that display time-dependent viscosity and/or yield-stress response upon the application of a fixed deformation, while recovering their original structured-state when the deformation is discontinued. Thixotropic effects are presents in many different systems and applications, ranging from food products, such as ketchup, to metals, such as molten aluminum. In this work we present a first attempt to simulate the rheological properties of thixo-viscoplastic flows using a Smoothed Particle Hydrodynamic (SPH) method. The study set up is a 2D flow around a circular cylinder as well as a simple shear flow between parallel plates to validate our numerical results. SPH solutions are compared with simulations performed using the open-source Finite Volume Method solver RheoTool, based on OpenFOAM. The viscoplastic model used in this work is the Papanastasiou model combined with a recently developed microstructural one, in order to include thixotropy. In this thixo-viscoplastic framework, we analyze the flow properties in terms of yield-fronts, streamlines and structure-parameter fields at different Bingham and Thixotropy numbers, through microstructural thixotropic and yield-stress parameters variation. Obtained results show an important novelty: an asymmetry in the thixo-viscoplastic flow around the cylinder. • First attempt to simulate thixo-viscoplastic flows using SPH. • 2D flow around a circular cylinder as well as a simple shear flow are analyzed. • Papanastasiou model is combined with a microstructural one to include thixotropy. • Flow properties are analysed using different Bingham and Thixotropy numbers. • Main finding is an asymmetry in the thixo-viscoplastic flow around a cylinder.

Finite Element Model Construction and Cutting Parameter Calibration of Wild Chrysanthemum Stem

Due to a lack of an accurate model in finite element simulation of mechanized harvesting of wild chrysanthemum, the stem of wild chrysanthemum in the harvesting period is taken as the research object. ANSYS Workbench 19.0 software and LS-DYNA software (LS-PrePOST-4.3-X64) are used to calibrate the finite element simulation model of wild chrysanthemum stem cutting. The stem diameter distribution at the cutting height of the chrysanthemum is obtained. The maximum shear forces at different diameters (7 mm, 8 mm, 9 mm, 10 mm, and 11 mm) within the cutting range are determined as 120.0 N, 159.2 N, 213.8 N, 300.0 N, and 378.2 N, respectively, by using a biomechanical testing machine and a custom-made shear blade. The Plastic_Kinematic failure model is used to simulate the cutting process by the finite element method. The Plackett–Burman test is employed to screen out the test factors that significantly affect the results, namely, the yield stress, failure strain, and strain rate parameter C. The regression model between the shear force and significant parameters is obtained by central composite design experiments. To obtain the model parameters, the measured values are substituted into the regression equation as the simulation target values. In other words, the yield stress is 17.96 MPa, the strain rate parameter C is 87.27, and the failure strain is 0.0387. The maximum shear force simulation test is carried out with the determined parameters. The results showed that the maximum error between the simulated and the actual value of the maximum shear force of wild chrysanthemum stems with different diameters is 7.8%. This indicates that the calibrated parameters of the relevant stem failure model can be used in the finite element method simulation and provide a basis for subsequent simulations.

Parallel-Disk Viscometry of a Viscoplastic Hydrogel: Yield Stress and Other Parameters of Shear Viscosity and Wall Slip.

The rheology, i.e., the flow and deformation properties, of hydrogels is generally a very important consideration for their functionality. However, the accurate characterization of their rheological material functions is handicapped by their ubiquitous viscoplasticity and associated wall slip behavior. Here a parallel-disk viscometer was used to characterize the shear viscosity and wall slip behavior of a crosslinked poly(acrylic acid) (PAA) carbomer hydrogel (specifically Carbopol® at 0.12% by weight in water). It was demonstrated that parallel-disk viscometry, i.e., the steady torsional flow in between two parallel disks, can be used to unambiguously determine the yield stress and other parameters of viscoplastic constitutive equations and wall slip behavior. It was specifically shown that torque versus rotational speed information, obtained from parallel-disk viscometry, was sufficient to determine the yield stress of a viscoplastic hydrogel. Additional gap-dependent data from parallel-disk viscometry could then be used to characterize the other parameters of the shear viscosity and wall slip behavior of the hydrogel. To investigate the accuracy of the parameters of shear viscosity and apparent wall slip that were determined, the data were used to calculate the torque values and the velocity distributions (using the lubrication assumption and parallel plate analogy) under different flow conditions. The calculated torques and velocity distributions of the hydrogel agreed very well with experimental data collected by Medina-Bañuelos et al., 2021, suggesting that the methodologies demonstrated here provide the means necessary to understand in detail the steady flow and deformation behavior of hydrogels. Such a detailed understanding of the viscoplastic nature and wall slip behavior of hydrogels can then be used to design and develop novel hydrogels with a wider range of applications in the medical and other industrial areas, and for finding optimum conditions for their processing and manufacturing.

The Sensory Quality and the Physical Properties of Functional Green Tea-Infused Yoghurt with Inulin.

The purpose of this study was to investigate the influence of the addition of inulin (3%, 6% and 9%) to green tea-infused set type yoghurt on its sensory quality and physical properties. Yogurts were made by combining green tea with milk and inulin and inoculated with freeze-dried starter cultures YO-122. Incubation was conducted at 43 °C for approximately 4.5 h until a pH value of 4.5–4.6 was achieved. For the prepared yoghurts, a panel of experts (n = 10) was selected, characterized 35 attributes and conducted a sensory quality assessment of these yoghurts using the Quantitative Descriptive Profile method. Additionally, instrumental analyses such as yield stress, adhesiveness, firmness, physical stability and color parameters were also carried out. The use of green tea infusion increased the perception of green tea flavor, bitterness, astringency, dark color of the yoghurt and the existing whey, which worsened the overall sensory quality of the yoghurt. The addition of inulin (9%) to the green tea yoghurt, increased the perception of sweet, peach flavor and aroma and improved the firmness of the yoghurt while reducing the perception of sour taste, which improved the sensory quality of the yoghurt. Both inulin and green tea affected the physical properties of the yoghurts, causing an increase in the yield stress (43%, and 20%, respectively) and deteriorated the stability of the yoghurts. Green tea affected the color of the yoghurts, causing the lightness to decrease. The L* parameter decreased from 89.80 for the control sample to 84.42 for the green tea infused yoghurt. The use of infused green tea in yoghurt production makes it necessary to use ingredients that will neutralize its adverse effects on sensory quality and physical parameters of yoghurt, and such an additive can be prebiotic fiber–inulin at a concentration of 9%.

Fully developed free convective flow of a Bingham fluid in a circular pipe with permeable wall

The present work focuses on the convection flow of a Bingham liquid in a circular pipe with permeable wall using nonlinear density temperature variation (NDT) relationship. The novelty of this communication is to study the impression of yield stress, NDT parameter on convective flow of Bingham liquid in a circular pipe with heat source. The governing flow equations are nonlinearly coupled and therefore complex to solve. Hence, perturbation method is applied to transform into linear ordinary differential equation to obtain the velocity and temperature fields. The expressions for velocity, plug flow velocity, temperature, plug flow temperature and heat transfer rate are derived. The outcomes of heat source parameter, permeable parameter, slip parameter and yield stress parameter on the fluid momentum and dimensionless temperature are obtained. The velocity field decreases with increase in yield stress and for negative values of NDT parameter. The increase in the NDT parameter increases the rate of heat transfer. When the yield stress and permeability parameter , our results concur with [Bhargava, R., and R. S. Agarwal. 1979. “Fully Developed Free Convection Flow in a Circular Pipe.” Indian Journal of Pure and Applied Mathematics 10 (3): 357–365]. The results obtained for the flow characteristics reveal many interesting behaviours that warrant further investigation on the non-Newtonian fluid phenomena and NDT variation.

Sodium Alginate and Chitosan as Components Modifying the Properties of Inulin Hydrogels.

The aim of the study was to investigate the influence of addition of sodium alginate (SA) and chitosan (CH) on the properties of inulin hydrogels. Inulin hydrogels (20 g/100 g) containing various additions (0.0, 0.1, 0.3, and 0.5 g/100 g) of SA and CH were produced. The hydrogels’ properties were assessed based on the volumetric gel index, microstructure, yield stress, texture, stability, and color parameters. According to the findings, the inclusion of these polysaccharides had no influence on the gelation ability of the inulin solution. The physical properties of the hydrogels containing SA or CH differed from hydrogels containing only inulin (INU). The obtained microstructural pictures revealed that the addition of SA and CH resulted in the formation of hydrogels with a more compact, smooth, and cohesive structure. Consequently, they had higher yield stress, strength, and spreadability values than INU hydrogels. The addition of chitosan in comparison with sodium alginate also had a greater effect in strengthening the structure of hydrogels, especially at the level of 0.5 g/100 g. For example, the addition of this amount of SA increased the yield stress on average from 195.0 Pa (INU) to 493.6 Pa, while the addition of CH increased it to 745.3 Pa. In the case of the strength parameter, the addition of SA increased the force from 0.24 N (INU) to 0.42 N and the addition of CH increased it to 1.29 N. In the case of spreadability this increase was from 2.89 N * s (INU) to 3.44 N * s (SA) and to 6.16 N * s (CH). Chitosan also caused an increase in the stability of inulin hydrogels, whereas such an effect was not observed with the addition of sodium alginate. The gels with the addition of SA and CH also had significantly different values of color parameters. Inulin–alginate hydrogels were characterized by higher values of the color parameter a *, lower values of the color parameter b *, and in most concentrations higher values of the color parameter L * compared to inulin–chitosan hydrogels. Based on the collected data, it can therefore be concluded that through the addition of sodium alginate and chitosan, there is a possibility to modify the properties of inulin hydrogels and, consequently, to better adapt them to the characteristics of the pro-health food products in which they will be used.

Effect of selected organic additives on the properties of magnesia-chromite refractories

The addition of carbon nanomaterials influences the variety of properties, of cementitious composites. Despite the multiple researches in the topic of properties of the hardened cement materials the influence of the Mutiwall Carbon Nanotubes [MWCNT] on rheological parameters of the cement mortars is not sufficiently described. Research shows that rheological properties of cement mortars with the MWCNTs, determined with the use of Viscometer NT, proved to be strongly dependent on the sonication time and amount of MWCNT, added. Increase of sonication time of MWCNT suspension with surfactant and decrease of amount of MWCNT caused increment in fluidity while yield stress parameter and plastic viscosity parameter decreased.

Crack-Bridging Property Evaluation of Synthetic Polymerized Rubber Gel (SPRG) through Yield Stress Parameter Identification.

Yield stress parameter derivation was conducted by stress-strain curve analysis on four types of grout injection leakage repair materials (GILRM); acrylic, epoxy, urethane and SPRG grouts. Comparative stress-strain curve analysis results showed that while the yield stress point was clearly distinguishable, the strain ratio of SPRG reached up to 664% (13 mm) before material cohesive failure. A secondary experimental result comprised of three different common component ratios of SPRG was conducted to derive and propose an averaged yield stress curve graph, and the results of the yield stress point (180% strain ratio) were set as the basis for repeated stress-strain curve analysis of SPRGs of up to 15 mm displacement conditions. Results showed that SPRG yield stress point remained constant despite repeated cohesive failure, and the modulus of toughness was calculated to be on average 53.1, 180.7, and 271.4 N/mm2, respectively, for the SPRG types. The experimental results of this study demonstrated that it is possible to determine the property limits of conventional GILRM (acrylic, epoxy and urethane grout injection materials) based on yield stress. The study concludes with a proposal on potential application of GILRM toughness by finite element analysis method whereby strain of the material can be derived by hydrostatic pressure. Comparative analysis showed that the toughness of SPRG materials tested in this study are all able to withstand hydrostatic pressure range common to underground structures (0.2 N/mm2). It is expected that the evaluation method and model proposed in this study will be beneficial in assessing other GILRM materials based on their toughness values.

Numerical Study on Generalized Heat and Mass in Casson Fluid with Hybrid Nanostructures.

The rheological model for yield stress exhibiting fluid and the basic laws for fluid flow and transport of heat and mass are used for the formulation of problems associated with the enhancement of heat and mass due to dispersion of nanoparticles in Casson. The heat and mass transfer obey non-Fourier’s laws and the generalized Fick’s law, respectively. Model problems are incorporated by thermal relaxation times for heat and mass. Transfer of heat energy and relaxation time are inversely proportional, and the same is the case for mass transport and concentration relaxation time. A porous medium force is responsible for controlling the momentum thickness. The yield stress parameter and diffusion of momentum in Casson fluid are noticed to be inversely proportional with each other. The concentration gradient enhances the energy transfer, and temperature gradient causes an enhancement diffusion of solute in Casson fluid. FEM provides convergent solutions. The relaxation time phenomenon is responsible for the restoration of thermal and solutal changes. Due to that, the thermal and solutal equilibrium states can be restored. The phenomenon of yield stress is responsible for controlling the momentum boundary layer thickness. A porous medium exerts a retarding force on the flow, and therefore, a deceleration in flow is observed. The thermal efficiency of Casson fluid is greater than the thermal efficiency of Casson fluid.

Bubble entrapment condition in Bingham materials

We investigate the entrapment condition of initially spherical and ellipsoidal Newtonian bubbles in viscoplastic materials using direct numerical simulations. For a spherical bubble, the entrapment condition depends on the balance between the buoyancy force and the force exerted by the yield stress of the viscoplastic material. For non-spherical bubbles, surface tension may yield the surrounding material to minimize the surface energy of the bubble. The yielding of the surrounding material by surface tension force facilitates the rising motion of bubbles. Although surface tension may yield the surrounding material and start the rising motion, the bubble may get entrapped later if the stress exerted by buoyancy force is less than the yield stress of the material. We evaluate the yield-stress parameter for different bubble shapes over a range of non-dimensional parameters to predict the critical yield-stress parameter for the entrapment of a bubble. • The critical yield stress parameter decreases at very high viscosity ratios. • The yield stress parameter is a constant at low viscosity ratios. • Yield stress resistive force depends on the maximum cross-sectional area normal to the buoyancy. • The critical yield stress parameter is independent of the initial shape of the bubble. • Non-spherical bubbles may be momentarily mobile due to surface tension effects.