Dilatant Fluids Research Articles

Hysteroscopic removal of a heterotopic cervical pregnancy to preserve a patient’s intrauterine sac

To introduce a case of removing the heterotopic cervical pregnancy while preserving the normal gestational sac in the uterine cavity by hysteroscopic surgery under ultrasound guidance. Video description of the case and surgical procedure. Hospital affiliated to university. A 35-year-old woman, G7P1A5L1, was admitted with a heterotopic cervical pregnancy 21 days after IVF-ET (the corrected gestational age was 5+2 weeks). The serum β-hCG level was 24,530.00 mIU/ml at the corrected gestational age of 5+3 weeks. The ultrasound examination on the day of admission showed that there was a gestational sac in the cervical canal (1.5×0.8×0.5 cm, yolk sac visible) and another sac in the intrauterine cavity (1.2×1.2×1.1 cm, yolk sac visible). The pregnant woman and her partner strongly urged the removal of the cervical gestational sac and continuing the intrauterine pregnancy to term. After the Institutional Review Board (IRB) approval was obtained, hysteroscopic surgery with bipolar resectoscope and transabdominal ultrasound guidance was used to resect the heterotopic cervical pregnancy while preserving the intrauterine gestational sac. The heterotopic cervical pregnancy was completely resected by hysteroscopy, and the normal gestational sac in the uterine cavity was successfully preserved. Ultrasound-guided hysteroscopic surgery allowed us to successfully preserve the intrauterine pregnancy while removing the cervical pregnancy completely. During the operation, the dilation pressure and the flow rate of the dilation fluid was kept as low as possible to avoid excessive intrauterine pressure and excessive dilation fluid entering the intrauterine cavity, which could have had adverse effects on the intrauterine pregnancy sac. No surgical-related or anesthesia-related complications occurred. The pathological results confirmed placental villi and decidual tissue. The One-month follow-up ultrasonography showed a live single intrauterine pregnancy with cardiac activity. Hysteroscopic removal of a heterotopic cervical pregnancy under ultrasound guidance can be safely performed while successfully preserving an ongoing intrauterine pregnancy.

Forced convective power-law fluid flow through porous annular sector duct

In this paper, we discuss the forced convective heat transfer of power-law fluid flow through porous annular sector duct by applying the Brinkman-extended Darcy flow model. A strongly implicit procedure (SIP) is utilized to solve the algebraic momentum and energy equations which was discretized by using the finite volume method (FVM). The effects of permeability factor and power-law index corresponding to the Brinkman-extended Darcy flow model and power-law fluid, respectively, on flow and heat transfer rate are carried out numerically and graphically against different values of parameters corresponding to geometrical configuration. In the pseudo-plastic fluids, a maximum decrease of more than [Formula: see text] has been observed in [Formula: see text], whereas maximum decrease in dilatant fluid is around [Formula: see text], when we increase the values of k. A decrease of 16.02% in Nu has been carried out in pseudo-plastic fluid, whereas unforeseen decrease in Nu has been observed in both Newtonian and dilatant fluids comparably pseudo-plastic fluid for particular values of k.

Free convection of Ostwald-de Waele fluid within square enclosure equipped with heat-generating circular solid: MRT-LBM simulation

BackgroundNon-Newtonian fluids are frequently present in many natural phenomena and industrial processes. This research focuses on free convection of Ostwald-de Waele fluid in a square enclosure equipped with a conducting circular body of constant internal volumetric heat flux. MethodsThe multiple-relaxation-time lattice Boltzmann approach is used for the numerical simulations of this physical problem. The 2-dimensional 9-discrete velocity (D2Q9) model is applied to the hydrodynamic field and the 2-dimensional 5-discrete velocity (D2Q5) model is used to thermal field. The bounce-back condition coupled with the quadratic interpolation is employed at circular boundaries. Significant findingsThe results show that the increase in the volumetric heat generation reverses, partially or completely, the direction of heat transfer on the hot left wall. Moreover, the employment of a dilatant fluid instead of pseudoplastic and Newtonian fluids leads to an increase in the maximum temperature in the case of a heat-generating obstacle.

Case-Wise Study of Thermal Radiation in Dilatant and Pseudoplastic Fluid Flows: A Detailed Numerical Approach

Case-Wise Study of Thermal Radiation in Dilatant and Pseudoplastic Fluid Flows: A Detailed Numerical Approach

Non-similar solution for a power-law fluid flow over a moving wedge

Heat transport (HT) efficiency in boundary layer flow (BLF) across wedges is critical for many industrial processes, as well as aerospace and defence research. The HT analysis in a power-law fluid along a moving permeable wedge is described in this paper. A changeable parameter is the injection velocity at the wedge surface. The governing equations are dimensionless, and the shooting technique is used to achieve a non-similar solution. Graphs depict the impacts of various factors on the velocity and temperature contours, local Nusselt number, and skin friction coefficient. The results show that the dilatant fluid has a velocity decline near the wedge surface and achieves its maximum velocity away from the wedge surface. The findings of this study may aid in the development of better HT systems for a variety of applications.

Nonlinear convection of MHD radiative non-Newtonian power law fluid due to exponentially stretched surface with dissipation and Joule heating effects

Present analysis deals with the impact of nonlinear convection on MHD non-Newtonian fluid flow considering exponentially stretched sheet through porous media. Additionally, the effects of radiation, Joule heating and energy dissipation have been taken into account. The considered flow situation of nonlinear PDEs is transmuted to nonlinear ODEs using similarity analysis. The numerical computations are derived using a fourth-order Runge–Kutta scheme with a shooting technique. Meaningful observations are discussed for velocity and energy profiles. Further, the impact of pertinent parameters considering pseudoplastic fluids [Formula: see text] and dilatant fluids [Formula: see text] is briefed through graphs. It is noted that the escalation in the values of the power-law index declines the velocity and energy profile. Higher values of the nonlinear parameter decline the energy profile.

Entropy analysis of a Sisko nanofluid on a stretching sheet under the Hall effect

The novelty of this paper is examining the impacts of Hall currents on Sisko nanofluid slip flow generated by an exponentially stretching sheet in the existence of entropy generation. Entropy generation assessment, Brownian, thermophoresis and Bejan numbers during convection flow are explored in the presence of the Hall effect. The pertinent parameters are Hall parameter m, a magnetic field parameter M, Brownian motion parameter [Formula: see text], thermophoresis parameter [Formula: see text], generalized thermal Biot number [Formula: see text], generalized velocity slip parameter [Formula: see text] and material parameter of Sisko fluid A. The changes in pertinent parameters on principal and secondary velocities, entropy generation and temperature are discussed. The coefficients of local skin friction, Brownian, thermophoresis and Nusselt/Sherwood numbers are expressed in a tabular structure. Two different kinds of power-law nanofluid, Pseudoplastic [Formula: see text] and dilatant fluid [Formula: see text] are considered. The current results exposed that growth in magnetic field parameter diminishes the nanofluid axial velocity and boosts the profiles of temperature, secondary nanofluid velocity and nanoparticle volume fraction. The coefficients of local skin friction are enhanced according to a growth in the magnetic field factor. The Pseudoplastic fluid supports the velocity, temperature and nanoparticle volume fraction profiles compared to the dilatant fluid. The local entropy generation number, Bejan number, local skin friction coefficients and local Nusselt/Sherwood numbers are influenced by the pertinent parameters.

Bioconvection on Non-Newtonian Magnetohydrodynamics Carreau Nanofluid with Activation Energy and Binary Chemical Reaction in Darcy Forchhiemer Porous Medium

In this present research, suspensions of gyrotactic micro-organisms on non-newtonian carreau nanofluid with activation energy and binary chemical reaction is examined which is implanted under Darcy Forchhiemer porous medium. Similarity transformations are used to convert the governing equation into a highly nonlinear ODE’s. Fifth-order Runge Kutta-Fehlberg method using shooting technique is utilized to solve ODE’s. Velocity, temperature, concentration, and density of motile gyrotactic microorganisms profile were depicted graphically and explained briefly. It is observed that activation energy enhances the concentration profile of both pseudoplastic and dilatant fluids. Present results is compared with previously published work which is found to be in good agreement.

Micro Electro-Osmotic Thrusters of Power-Law Fluids for Space Propulsion.

In this article, electro-osmotic thrusters (EOTs), which are full of non-Newtonian power-law fluids with a flow behavior index n of the effective viscosity, are theoretically investigated in a microchannel. Different values of the flow behavior index represent two kinds of non-Newtonian power-law fluids, pseudoplastic fluids (n < 1) and dilatant fluids (n > 1), which have not yet been considered to be used as propellants in micro-thrusters. Analytical solutions of the electric potential and flow velocity are obtained using the Debye-Hückel linearization assumption and the approximate scheme of hyperbolic sine function. Then, thruster performances of power-law fluids, including specific impulse, thrust, thruster efficiency, and thrust-to-power ratio, are explored in detail. Results show that these performance curves strongly depend on the flow behavior index and electrokinetic width. It is noted that the non-Newtonian pseudoplastic fluid is most suitable as a propeller solvent in micro electro-osmotic thrusters owing to its improving or optimizing deficiencies in the performances of the existing Newtonian fluid thrusters.

Characterization of sacha inchi (Plukenetia volubilis) and taro (Colocasia esculenta) flours with potential application in the preparation of both gluten-free and high protein foods.

Background: Interest in alternative sources of tubers and legumes has increased in recent years because of the constant search for raw materials that provide bioactive compounds with antioxidant potential benefits for consumers. The functionality of new raw materials is sought through physical and/or chemical modifications to develop and innovate new foods. The objective of this study was to characterize taro (TF) (Colocasia esculenta) and sacha inchi (Plukenetia volubilis) flours, obtained by the wet (SIF-WM) and defatted method (SIF-DM), as an alternative for the formulation of new functional foods. Methods: The free polyphenols of the different mixtures were analyzed, and the antioxidant properties of the extracts obtained were measured using ABTS.* (2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid). The ABTS radical method, which reacts with the phenolic compounds of the food matrix, using Trolox as a standard. The blends were subjected to pasting analysis, flow profile tests, determination of viscoelastic properties (temperature sweep). Characterization of common microorganisms in these foods was performed. Results: The highest protein value was obtained in the sacha inchi flour obtained by the defatted method (72.62). The majority of components in taro were carbohydrates (85.4%). About antioxidant and determination of free polyphenols, taro flour obtained values of 2.71 µmol ET/g and 7.47 mg EAG/g, higher than Sacha inchi flours. In the rheological analysis (pasting properties, flow profile, and viscoelasticity), we observed that adding taro flour in different mixtures increases the viscosity peak and a lower breakdown, while there was an increase in setback. Except for defatted sacha flour, the others presented a flow index &gt;1 before heating, showing a dilatant fluid behavior. The presence of Taro flour improves gel formation and stability. Staphylococcus aureus and Salmonella were present in the taro flour. Conclusions: The flours analyzed represent a raw material with great potential for the development of gluten-free foods with functional properties.

Viscous dissipation and Joule heating effects on hydro-thermal power law nanofluid through annular duct

This study presents a mathematical model along with numerical simulation to investigate the viscous dissipation and Joule heating effects on electrically conducting magnetohydrodynamics (MHD) forced convection non-Newtonian power law nanofluid flow through annular sector duct. Hydro-thermal power law nanofluid flow through annular sector duct is not investigated in the presence of Joule heating and viscous dissipation effects. The consideration of Joule heating and viscous dissipation effects makes it very much novel in its own right. The main objective of this work is to explore the Joule heating and viscous dissipation effects on hydro-thermal power law nanofluid. Both Copper, Cu/Titanium oxide, TiO2 nanoparticles with base fluid water have been taken as a power law model. Numerically simulation is carried out for viscous, incompressible and steady laminar fully developed fluid flow with constant properties, by using the finite volume method (FVM) and strongly implicit procedure (SIP). It has been observed that viscous dissipation effect on temperature profiles is enhanced in the absence of magnetic field/at lower value of Ha, however, when nanoparticles’ concentration is increased, the effect of magnetic field slightly decreases. Furthermore, by adding Cu nanoparticles from 0% to 5%, we observe the increment in average Nusselt number, Nu up to 16.01% and 16.07% in pseudo-plastic and dilatant fluids, respectively, at [Formula: see text].

Dilatant-Fluid Torsional Vibration Damper for a Four-Stroke Diesel Engine Crankshaft

Abstract This paper presents a study of a viscous torsional vibration damper for a crankshaft of a four-stroke diesel engine. The reliable operation of a widely used silicone-type viscous damper depends on the ability of the silicone oil to absorb the energy of torsional vibrations. The non-Newtonian shear flow of the silicone oil interlayer, characterised by a reduction in the shear-rate-dependent viscosity and a moment of the drag forces, negatively affects damping characteristics. A torsional vibration damper, filled with a shear-thickening fluid, was considered and a rheological approach, based on viscosity growth with the shear rate increase, was applied. For such a damper, larger velocity gradients correspond to the higher values of a viscous force, which decreases torsional vibration. The parameter of damper effectiveness (defined by the fluid flow index, values of the damper gaps, torsional vibration amplitude and frequency) was implemented. It has been established that the efficiency of the torsional vibration damper filled with a dilatant fluid does not depend on the damper dimensions and gaps and significantly increases when a shear-thickening fluid is used instead of silicone oil or a Newtonian fluid. At higher values of the flow index, when the non-Newtonian flow becomes distinct, torsional vibrations are damped more effectively. Critical vibration amplitudes at high-velocity gradients, in turn, increase the damping effect as the moment of the drag forces and flow index are power-law related.

Numerical Investigation of Vibration Suppression for the Combined Device of Non-Newtonian Fluids Coupled Elastic Baffle

Tuned liquid dampers (TLDs) have been broadly applied to suppress structural vibrations. In the present study, a novel vibration mitigation device consisting of non-Newtonian fluids coupled with an elastic baffle is proposed. The fluid-structure interaction is studied numerically. To optimize the system, different fluids, including the Bingham fluid, the Pseudoplastic fluid, and the Dilatant fluid are used as the damping fluids and the vibration suppression ability of each fluid is studied. Moreover, the energy dissipation mechanisms of different liquids are obtained. The results show that the optimal vibration suppression in the container without a baffle can be achieved by using the Bingham fluid. In this case, the average amplitude decay rate of the container is 12.662% with about 0.199% improvement in the damping ratio when compared to water. In the container with an elastic baffle, however, both the Pseudoplastic fluid and the Dilatant fluid outperform water in the damping capacity. The average amplitude decay rates of these fluids are 50.960% and 43.794%, respectively. Moreover, their damping ratios are 0.035% and 0.019% higher than that of water, respectively.

Mechanics of heated Rabinowitsch fluid in elliptic vertical duct: Peristalsis and analytical study

This work consists of the analytical study of the peristaltic flow of heated non-Newtonian fluid flow through an elliptical duct. The flow characteristics of Pseudoplastic and Dilatant fluids are analyzed in a vertically held elliptic duct by considering the Rabinowitsch fluid model. The mathematical model is processed to a dimensionless analysis by employing adequate nondimensional variables and extended wavelength approximation. The resulting PDEs are solved analytically in the elliptic domain using the explicit boundary condition form. A simpler second-degree polynomial is presented to get the solution of temperature. These analytical solutions are examined in detail by graphical analysis. It is found that the flow velocity of Pseudoplastic fluid is more prominent than Dilatant fluid in the vicinity of the centerline. The earlier and later fluids have a maximum axial speed at the channel’s mean and close to the peristaltic boundary. The greater buoyancy force (Grashof number) enhances the Pseudoplastic fluid’s velocity but diminishes the flow velocity of Dilatant fluid. Moreover, it is noticed that the aspect ratio has less impact, and the Grashof number has an effective influence on pressure rise. The streamlines of Rabinowitsch fluid break into vortices near the deformed wall. The vortices are comparatively less in the count for Dilatant fluid than Pseudoplastic fluid for quick flow and a more significant Grashof number.

Interaction of nanoparticles with micro organisms under Lorentz force in a polymer liquid with zero mass flux

BackgroundRheological fluids enduring bio convection are gaining great attention in modern day industrial, technological and several manufacturing industries. Such flows are evident in chemical and mining industry, biomedical flows, and many other fields of science and engineering. Among the many other rheolgical liquids, Sutterby fluid model is significant due to its characteristics of Pseudoplastic and dilatant fluids. It portrays dilute polymer solutions, which has numerous applications in industrial practice. MethodsIn this theoretical research two-dimensional hydromagnetic stagnation point flow of Sutterby bio convective fluid through an elastic surface has been discussed. The mathematical model of governed problem is transformed into a set of ordinary differential equations using similarity transformation. These nonlinear coupled ordinary differential equations are handled by using shooting scheme (numerical technique). Significant findingsInfluence of all physical constraints for temperature, concentration of gyrotactic microorganism and velocity profiles are presented graphically. Local heat & mass flux and density of microorganisms (Physical quantities of interest) are presented numerically through bar charts.

Shear Flows of Dilatant Fluids with Limited Shear Rates: Analytical Results and Linear Stability Analysis

In this paper, we study the simple shear flows of a class of dilatant fluids with a limited shear rate. This class of fluids is characterized by shear thickening behavior in which the apparent viscosity tends to infinity as the modulus of the stress approaches a finite threshold. The apparent viscosity function is a logarithmic type with two material parameters. We considered this specific form because it fits very well with the flow curves of some granular suspensions for specific values of the material parameters. Despite the nonlinearity of the constitutive law, it is possible to determine explicit steady-state solutions for a simple shear flow, namely (i) the channel flow; (ii) the flow between coaxial cylinders, and (iii) the flow down an inclined plane. We performed a two-dimensional linear stability analysis to investigate the onset of possible instabilities of the steady basic flow, putting into evidence the dependency of the critical Reynolds number on the material parameters.

Buoyancy-Induced Instability of a Power-Law Fluid Saturating a Vertical Porous Slab

Abstract Many engineering applications involve porous media and rely on non-Newtonian working fluids. In this paper, the seepage flow of a non-Newtonian fluid saturating a vertical porous layer is studied. The buoyant flow is thermally driven by the boundaries of the porous layer, which are permeable surfaces kept at different temperatures. In order to model the seepage flow of both shear-thinning (pseudoplastic) and shear-thickening (dilatant) fluids, reference is made to the Ostwald-de Waele rheological model implemented via the power-law extended form of Darcy's law. The basic stationary flow is parallel to the vertical axis and shows a single-cell pattern, where the cell has infinite height and can display a core-region of enhanced/inhibited flow according to the fluid's rheological behavior. By applying small perturbations, a linear stability analysis of the basic flow is performed to determine the onset conditions for a multicellular pattern. This analysis is carried out numerically by employing the shooting method. The neutral stability curves and the values of the critical Rayleigh number are computed for different pseudoplastic and dilatant fluids. The behavior of a Newtonian fluid is also obtained as a limiting case.

Hydromagnetic Non-Newtonian Fluid Flow in a Convergent Conduit

In the present study, a hydromagnetic non-Newtonian (dilatant) fluid flow in a convergent conduit, in the presence of a variable transverse magnetic field, has been investigated. The governing nonlinear partial differential equations are reduced to system of ordinary differential equations. These equations are solved numerically by the collocation method and implemented in MATLAB. The study determines the flow profiles and the impact of the flow parameters on the flow variables. Joule heating, variable viscosity, viscous dissipation, skin friction, the rate of heat transfer, and the induced magnetic field are taken into account. The obtained results are presented graphically and the impact of varying flow parameters on the skin friction coefficient and the Nusselt number is presented in tabular form. These results indicate that an increase in the Reynolds number, Eckert’s number, and the Joule heating parameter increases the fluid’s velocity, while an increase in the Hartmann number and the unsteadiness parameter decreases the convective heat transfer and the fluid’s velocity. Further, the skin friction coefficient decreases with increase in the Reynolds number, the Hartmann number, and the Joule heating parameter. Therefore, a less viscous fluid is appropriate to facilitate the fluid’s motion, but the presence of high magnetic field reduces the fluid’s motion.

Analytical Procedure for the Flow of a Carreau-Yasuda Fluid Through the Diseased Tapered Inclined Artery Subject to Heat Transfer and Chemical Reactions

This paper demonstrates the implications of heat transfer and chemical reactions by considering the flow of a Carreau-Yasuda fluid through the diseased tapered inclined artery. The analysis has performed on the artery with mild stenosis. The analytical solution has been obtained using the perturbation method due to its low Weissenberg number to get the blood velocity, the wall shear stress distribution, the temperature, the concentration, the resistance impedance and the stream function. The critical results in this study have depicted that the blood velocity for dilatant fluid is higher than that in viscous and pseudoplastic fluids in the core region of the artery. The value of blood velocity through a Newtonian fluid is extraordinarily lower than that through a Carreau-Yasuda fluid at the core region of the artery. The magnitude of blood velocity across the vertical artery is higher than those in the inclined and horizontal arteries inside the core region of the artery. The wall shear stress distributions are higher in the case of stenosis (diseased artery) than in no stenosis (healthy artery). The temperature transmission for the Carreau fluid is higher than that for the Carreau-Yasuda fluid. The flow resistance progressively increases as the depth of the stenosis increases. The size of the trapping bolus gradually increases, shifting toward the right at the diverging tapering artery, and it gradually increases, moving toward the left at the converging tapering artery. Finally, the streamlines are noticeably more comprehensive along the vertical artery and are higher than those in the inclined and horizontal arteries.

Effects of different viscous dissipation and Joule heating on electromagnetohydrodynamic flow of power-law fluid in the porous microchannel

Of concern in this paper is a theoretical investigation of Electromagnetohydrodynamic (EMHD) flow transport of a non-Newtonian power-law fluid through a porous microchannel based on the Brinkman-Forchheimer extended Darcy model. The impact of joule heating and different viscous dissipations (the Al-Hadharami term, Darcy term and Forchheimer term) on thermal transport was analysed by considering the EMHD flow through the porous microchannel. The governing nonlinear equations are solved numerically to analyse the characteristics of velocity and temperature distributions. Observing a Nusselt number variation for different parameter values is interesting. It also indicated from the effects that the heat transfer rate performed better for the pseudoplastic fluid than the dilatant fluid. It was also significantly influenced by different viscous dissipation terms. The apprehensible changes in the temperature profiles are found due to the additional viscous dissipation terms and joule heating shown in the channel’s middle layers for all the fluids.