Slip Velocity Research Articles

Melting and heat generating influences on radiative flow of two-phase magneto-Williamson nanofluid via stretchable surface with slippage velocity and activation energy

Melting heat and solutal transference in a magnetohydrodynamic flowing of Williamson nanofluid have been described, with the mathematical model guided by Arrhenius activation energy, chemically reactive species, and convective boundary restrictions. By implementing suitable similarity conversions, the regulating equations of partial differential equations (PDEs) (formed by continuity, impetus, energy, and concentricity components) are condensed to an arrangement of ordinary differential equations (ODEs). These commonalities are in nonlinear form, which includes the fluid’s velocity, heat, and concentration changes. Finally, the standard Keller box approach is used to solve this ODEs system computationally (KBM). Under the influence of regulating parameters, the computational results are tallied and displayed in suitable diagrams. The friction force factor, local Nusselt, and Sherwood values are tabulated. Furthermore, the velocity, energy, and concentration contours are plotted versus fluid thickness. The attributes of Williamson nanofluid flowing, melting heat transfer, and mass transference are debated in depth toward the end of this study. Among the most important outcomes that have been reached is that the rate of heat and solutal transport heightened between 52.5 and 55.2% by detraction of the magnetic field, Weissenberg number, and Brownian motion. We also found that there is an inverse relationship between the mass transmission and heat generating factor.

Decoding stress-strain parameters in FCC metals using digital constitutive analyses to devolve dynamic obstacle-strength factor and diffuse necking

Simulation codes use constitutive relations of work hardening to virtually predict shape change during metal forming. Recent analysis has shown that the modified Hollomon-type relation correlates to stress-aided thermal activation at obstacles for dislocation movement. The sweeping action of dislocation gives rise to strain and the dislocation intersections to strain rate sensitivity during work-hardening. The constitutive relation analyses (CRA) encompass fitting parameters which remain constant with strain and its validation is the precision to replicate the measured stress-strain diagram. In this study, digital constitutive analyses (DCA) are examined whereby the modelled-fit parameters are simultaneously numerically adjusted as strain proceeds. For bulk properties such as expended work, volume fraction of vacancy creation and mean slip velocity, CRA predictions have been validated. However, DCA enables the identification of defects being created with strain using derived obstacle-strength factor (αγ). The changes in mechanisms during work-hardening can be decoded using the αγ – γ plot whereby constant αγ indicate steady-state deformation and its rapid decrease, the start of diffuse necking. Thus, αγ is a composite factor of defects being continuously created whereas conventional α is a measure of the stored work up to that strain. The tensile data from polycrystalline super-pure aluminum tested at 78 K were used to validate the derived relations which were applied to the DCA of age-hardenable aluminum alloys tested at 298 K. The present work shows that integral replication of stress-strain diagram is essential, but a differential analysis is required to devolve the creation of crystal defects with strain.

A cationic type long-lasting drag-reduction agent based on reduced interfacial water film thickness for enhanced injection in low-permeability reservoirs

In water injection development of low-permeability reservoirs, the elevated flow resistance between the rock surface and the injected water results in enhanced injection pressure. Reducing the thickness of interfacial water film to expand flow radius is a new thought to achieve a decrease in injection pressure. In this work, a hydroxyl-containing cationic surfactant tetradecyl methyl dihydroxy-ethyl ammonium bromide (HTTAB) was designed and synthesized. The introduction of hydroxyl groups enhances the binding to the negatively-charged rock surface. HTTAB can modify the strong hydrophilic rock surface to a hydrophobic state, with the water contact angle increasing from 20.2° to 110.3°. HTTAB shows excellent drag-reducing effect, maintaining a drag reduction rate of over 30 % even after 30 PV of flushing. Particle Image Velocimetry (PIV) experiments show that after HTTAB adsorption, the interfacial slip velocity and centerline velocity can increase by 1.67 times and 33.66 % respectively, and the flow radius expands significantly. In addition, the thickness of the interfacial water film is obtained using Atomic Force Microscope (AFM). The results show that the thickness of the interfacial water film is reduced significantly from 79.42 nm to 8.85 nm. This study provides important guidance for the design of drag-reducing agents and the understanding of interfacial drag-reduction behavior.

Effects of magnetohydrodynamics and velocity slip on mixed convective flow of thermally stratified ternary hybrid nanofluid over a stretching/shrinking sheet

This paper undertakes a numerical exploration into the dynamics of fluid flow and heat transfer within the stagnation region of a mixed convection scenario involving thermally stratified ternary hybrid nanofluid. The study incorporates the impact of a magnetohydrodynamic and velocity slip, while also considering a permeable sheet that can stretch or shrink. The equations governed the flow problem are transformed into similarity equations using a similarity transformation. Then the similarity equations are solved utilizing the built in solver (bvp4c) in MATLAB. This flow problem has two solutions, as expected. Following that, the outcomes of the stability analysis show the viability and physical robustness of the first solution. Additionally, the study identifies magnetic, suction, and volume fraction as parameters capable of delaying turbulence onset in the boundary layer. Moreover, the heat transmission of the ternary hybrid nanofluid is enhanced by an increased volume fraction. It is important to note that the reported results specifically pertain to the combination of alumina, copper, and titania nanoparticles. Different combinations of nanoparticles may exhibits unique properties related to both flow behaviour and heat transmission.

Numerical stability of magnetized Williamson nanofluid over a stretching/shrinking sheet with velocity and thermal slips effect

A numerical investigation is carried out on multiple solutions over a stretching/stretching sheet to examine the influence of thermal radiation, Lorentz force, velocity, and thermal slips on Williamson nanofluid. Nanofluids have significant applications owing to their potential properties and versatility. The Navier-Stokes equations are converted in terms of PDEs, which are then altered to ODEs through suitable transformations. The novelty of the current study is to investigate the stability of the Williamson nanofluid with the Prandtl effect over stretching/stretching sheets. The numerical results are obtained by using the Runge-Kutta order 4th-method. The analysis observes two branches (dual solutions) for different parameters due to shrinking phenomena. Due to the non-uniqueness of the solutions, a stability analysis is implemented, and it is observed that the upper branch (first solution) is trustworthy. Dual solutions exist for a shrinking state ( λ 1 c ≤ λ 1 ≤ − 0.4578 ), the single branch exists when λ 1 > − 0.4578 , and no branch exists when λ 1 ≤ λ 1 c . The findings demonstrate that as the slips and heat parameters are improved, the boundary layer thickness for the multiple solutions declines. Furthermore, the present analysis reveals that when the Williamson parameter is enhanced, the dual solutions for the concentration and temperature profiles are also increased. A validation analysis is carried out with published work and excellent agreement is established.

A Study of the Friction Characteristics of Rubber Thermo-Mechanical Coupling.

The friction performance of tread rubber is related to the safety of the vehicle during driving, especially in terms of shifting speeds, cornering, and changing environmental factors. The experimental design used in this paper employed a self-developed automatic multi-working-condition friction tester to investigate the correlation between the friction coefficient of three tread formulations and various factors, including speed, pressure, temperature, side deflection angle, and lateral camber. This experimental study demonstrates that the coefficient of friction decreases with increasing load and increases with increasing sliding velocities due to changes in adhesion friction. Due to the increasing and decreasing changes in rubber adhesion and hysteresis friction caused by temperature, the coefficient of friction shows a tendency to increase and then decrease with the increase in temperature; thus, temperature has an important effect on the coefficient of friction. Based on the basic theory of friction and experimental research, the Dorsch friction model was modified in terms of temperature, and the analytical relationship between the rubber friction coefficient and the combined variables of contact pressure, slip velocity, and temperature was established, which is more in line with the actual situation of rubber friction. The model predictions were compared with the experimental results, and the error accuracy was controlled within 5%. This verifies the accuracy of the model and provides a theoretical basis for the study of rubber friction.

Fracture behavior and constitutive relations of Sn-3.0Ag-0.5Cu solder alloy at cryogenic temperature

The mechanical behavior, underlying fracture mechanism and constitutive relations of Sn-3.0Ag-0.5Cu (SAC305) solder alloy at cryogenic temperature through in-situ uniaxial tensile experiments were investigated over a wide temperature range of 293 K–77 K. The activation of deformation twin in the solder alloy contributes to improve the tensile strength and quasi-static toughness, and maintains the fracture elongation at 35–45% with the decline of ambient temperature. SAC305 solder alloy with a mixed mode of ductile and brittle fracture achieves the optimal balance of strength, ductility and toughness at 123 K, and the large mismatch between twins thickening rate (∼13 μm/s) and dislocation slip velocity (∼3.6 μm/s) finally leads to the brittle fracture at 77 K. In addition, Anand model as a unified viscoplastic constitutive law has been employed to describe the constitutive relations of SAC305 solder alloy and fails in fitting the stress-strain curves at invalid temperature below 233 K. Hollomon equation is conducted to perfectly characterize the constitutive relations of the alloy at temperatures lower than 233 K. The method for controlling the formation of deformation twins in the solder alloy and solder joints is really beneficial to solve the reliability problems for cryogenic electronics.

Computational analysis of magnetized Casson liquid stretching flow adjacent to a porous medium with Joule heating, stratification, multiple slip and chemical reaction aspects

This article aims to investigate the characteristics of thermo-solutal magnetohydrodynamic (MHD) non-Newtonian smart coating boundary layer flow of a stretching substrate adjacent to a porous medium, considering the influence of chemical reactions and thermal radiation subject to a transverse static magnetic field. A non-Darcy drag force model is deployed to capture both Darcy bulk drag and inertial Forchheimer (quadratic) drag effects. A diffusion flux model is deployed for radiative heat transfer. The Casson viscoplastic model has been utilized to simulate rheological characteristics. Due to polymeric slip effects, three slip phenomena are included at the wall (hydrodynamic, thermal and concentration) in the formulation. Furthermore, viscous dissipation and Ohmic heating (Joule dissipation) are also included. Robust scaling similarity variables are deployed to transform the governing partial differential equations into ordinary differential equations. Subsequently, the emerging dimensionless coupled nonlinear boundary value problem is solved utilizing the Bvp4c method in MATLAB version 2022. This numerical approach allows for a logical parametric examination of all key control parameters on the transport phenomena, enabling a comprehensive understanding of the system behavior. Validation with previous studies is included. Detailed graphical and tabular computations are included for velocity, temperature, concentration, skin friction, Nusselt number and Sherwood number, for the influence of Darcian parameter, Forchheimer inertial parameter, mixed convection, velocity (momentum) slip, magnetic number, Casson parameter, nonlinear thermal convection parameter, nonlinear concentration convection parameter, radiation parameter, thermal stratification parameter, Prandtl number, heat source/sink parameter, Eckert number, thermal slip parameter, Schmidt number, chemical reaction, solutal stratification parameter and solutal slip parameter. Detailed interpretation of the physics associated with these multiple effects is included. The simulations provide further insight into the transport characteristics of electromagnetic viscoplastic coating material manufacturing.

Transformer oil‐based Casson ternary hybrid nanofluid flow configured by a porous rotating disk with hall current

AbstractThe present work examines the 3D, incompressible, magnetohydrodynamic, mixed convective, and Darcy‐Forchheimer Casson /transformer oil ternary hybrid nanofluid flow configured by a porous rotatory disk. This research work takes into account the influences of hall current, thermophoresis, heat absorption/generation, Brownian motion, joule heating, chemical reaction, thermal radiation, activation energy, and velocity slip condition. The administrative partial differential equations (PDEs) that expound the problem are modified into a set of ordinary differential equations (ODEs) by imposing a similarity conversion, which is further solved numerically by adapting the worthy bvp4c scheme. The velocity, thermal, and mass profiles are delineated through graphs, and the features of skin friction coefficient, heat, and mass transmission are also explicated thoroughly via tables. One significant observation of this research is that the Casson parameter weakens transversal velocity whereas a reverse tendency is noticed against the radial velocity. Our obtained outputs affirm that Casson ternary hybrid nanofluid has respectively 10.93 % and 8.86% higher heat deliverance rate when compared to Casson nanofluid and Casson hybrid nanofluid. Besides, the Casson ternary hybrid nanofluid has respectively 33.68 % and 27.52% higher mass deliverance rate when compared to the Casson nanofluid and Casson hybrid nanofluid. Also, the sturdy values of the Casson parameter lessen the skin friction coefficient. The inferences derived from our research may advantageously be used in rotating types of machinery, medical equipment, gas turbine rotators, etc.

Recovery mechanisms of shale oil by CO2 injection in organic and inorganic nanopores from molecular perspective

CO2 injection is the feasible method to enhance shale oil recovery and has attracted extensive attention in recent years. Since shale reservoir has omnipresent nanoscale pores, understanding the underlying CO2-EOR mechanisms at the nanoscale is of critical importance. In this work, we study the structural and dynamic properties of CO2/nC8 systems in organic kerogen and inorganic quartz nanopores by molecular dynamic simulation and clarify the dominant EOR mechanisms of CO2 injection in various mineral nanopores. We find a large positive slip velocity occurs when single-phase nC8 flows in quartz nanopore while it is no-slip boundary condition in kerogen nanopore. The CO2-regulated nC8 in quartz nanopore is the joint effect of slip, competitive adsorption and viscosity reduction. In the first stage, CO2 extracts the first adsorption layer of nC8 by competitive adsorption and forms a CO2 film on the quartz surface. The CO2 film reduces the slip velocity between nC8 and quartz surface and weakens the nC8 flow capacity. After CO2 adsorption is saturated, the CO2 mixes with nC8 in all flow regions and the effective viscosity of nC8 starts decreasing at this stage. The flow capacity of nC8 rises dramatically due to the viscosity reduction mechanism of CO2. In kerogen nanopore, it is no-slip boundary condition and CO2 mixes with nC8 in all flow regions directly instead of preferably adsorbed on the surface. Viscosity reduction is the dominant mechanism to affect nC8 flow behavior and nC8 flow capacity is enhanced monotonically as CO2 injection. Our study advances the understanding of the recovery mechanisms of shale oil by CO2 injection on nanoscale and provides the theoretical foundation for the optimization of CO2-EOR in shale oil reservoirs.

A homogenized two-phase computational framework for meso- and macroscale blood flow simulations

Background and ObjectiveOwing to the complexity of physics linked with blood flow and its associated phenomena, appropriate modeling of the multi-constituent rheology of blood is of primary importance. To this effect, various kinds of computational fluid dynamic models have been developed, each with merits and limitations. However, when additional physics like thrombosis and embolization is included within the framework of these models, computationally efficient scalable translation becomes very difficult. Therefore, this paper presents a homogenized two-phase blood flow framework with similar characteristics to a single fluid model but retains the flow resolution of a classical two-fluid model. The presented framework is validated against four different sets of experiments. MethodsThe two-phase model of blood presented here is based on the classical diffusion-flux framework. Diffusion flux models are known to be less computationally expensive than two-fluid multiphase models since the numerical implementation resembles single-phase flow models. Diffusion flux models typically use empirical slip velocity correlations to resolve the motion between phases. However, such correlations do not exist for blood. Therefore, a modified slip velocity equation is proposed, derived rigorously from the two-fluid governing equations. An additional drag law for red blood cells (RBCs) as a function of volume fraction is evaluated using a previously published cell-resolved solver. A new hematocrit-dependent expression for lift force on RBCs is proposed. The final governing equations are discretized and solved using the open-source software OpenFOAM. ResultsThe framework is validated against four sets of experiments: (i) flow through a rectangular microchannel to validate RBC velocity profiles against experimental measurements and compare computed hematocrit distributions against previously reported simulation results (ii) flow through a sudden expansion microchannel for comparing experimentally obtained contours of hematocrit distributions and normalized cell-free region length obtained at different flowrates and inlet hematocrits, (iii) flow through two hyperbolic channels to evaluate model predictions of cell-free layer thickness, and (iv) flow through a microchannel that mimics crevices of a left ventricular assist device to predict hematocrit distributions observed experimentally. The simulation results exhibit good agreement with the results of all four experiments. ConclusionThe computational framework presented in this paper has the advantage of resolving the multiscale physics of blood flow while still leveraging numerical techniques used for solving single-phase flows. Therefore, it becomes an excellent candidate for addressing more complicated problems related to blood flow, such as modeling mechanical entrapment of RBCs within blood clots, predicting thrombus composition, and visualizing clot embolization.

Irreversibility and spectral analysis for nanofluid with melting and higher order slip effects

This work is intended to examine the impacts of first and second-order velocity slips, viscous dissipation, and melting on mixed convective flow of nickel zinc ferrite + SAE 20W-40 motor oil based nanofluid along a stretching or shrinking sheet for the first time. The multigrade 20W-40 motor oil is categorized by Society of Automotive Engineers (SAE). An irreversibility analysis has also been performed using the second law of thermodynamics. The resulting non-dimensional flow-governing equations are modified into ODEs (Ordinary Differential Equations) and then the numerical estimates are provided by adopting the spectral local linearization method. Next, the efficiency of the above-mentioned spectral procedure is verified through the maximum error norms. Finally, the influence of important parameters included in this evaluation on the flow profiles and physical quantities is systematically represented. Based on the findings, the melting effect enhances the heat transference rate by 24.6% and reduces entropy by 38.4%. The use of higher-order velocity slips and viscous dissipation effects results in a lower friction factor. In the presence and absence of ferrite particles, the streamline visualization is clarified. This type of simulation is extremely useful for the readers in considering the rates of cooling or heating at electromagnetic interfaces, industrial devices, orthopedic joint replacements, aircraft turbines, bone plate surgeries, and so on.

Numerical Investigation of Three-Dimensional Magnetohydrodynamic Flow of Ag 􀀀 H2O Nanofluid Over an Oscillating Surface in a Rotating Porous Medium

Objective: To investigate the three-dimensional flow of a nanofluid (Ag-water) over a stretchable vertical oscillatory sheet. This study involves considering fluctuating temperatures on the sheet and comparing them to the free stream temperature. The formulation of the unsteady boundary layer equations leading to the flow of nanofluid also takes into consideration the occurrence of the heterogeneous-homogeneous chemical reaction and thermal radiation. Method: The governing equations and the boundary conditions have been derived in a dimensionless form by using the appropriate transformations, and they are then solved using an EFDS (Explicit Finite Difference Scheme) in Matlab software. The Von-Neumann stability analysis is used to determine the method’s stability requirements for constant sizes of the grid. Findings: The physical factors impact on the concentration fields, temperature distribution, and velocity distribution were obtained and are studied by graphs and described in extensive detail. Convergence and stability requirements are attained in order to achieve accurate solutions. Novelty: In this study fluctuations in the temperature and stretching velocity of sheet on three-dimensional magnetohydrodynamic flow of Ag − H2O nanofluid over an oscillating surface through rotating porous are taken into account. Impacts of porous media permeability, velocity slip, magnetic fields, nanoparticle volume fraction, heat radiation, rotation, and homogeneous and heterogeneous chemical reaction parameters had all been attempted to be determined. Keywords: Oscillatory Surface, Heat transmission, Nonlinear PDE, Explicit Finite Difference Scheme, Nanoparticle

Thermal radiative and Hall current effects on magneto-natural convective flow of dusty fluid: Numerical Runge–Kutta–Fehlberg technique

This research article intends to examine the consequences of Hall impact on the natural convection of magnetohydrodynamic (MHD) fluid flowing and the thermal characteristics of the fluid flow which containing dusty particles via a vertical stretchable sheet. Slip velocity and convective boundary conditions are taken into consideration in this research article. The flow is mathematically described by partial differential equations. The governing equations are renovated into a group of nonlinear differential equations with the use of similarity conversations, which are then resolved numerically by applying Runge–Kutta–Fehlberg. The behavior of these physical factors on the rapidity and temperature profiles of the dust and fluid phases are exposed graphically in this article. Furthermore, frictional force and heat transfer are also examined and discussed. According to the investigation, the existence of suspended particles in the fluid lead to increment in momentum and thermal boundary layer thickness. The temperature of the fluid seems can be controlled by the significant parameter, such as it seem to be increase due to the magnetic, radiation, and Hall parameters, while it is seen to have decreased due to the slip thermal parameter. While the radiation accelerates up the fluid velocity, the magnetic parameter is excellent at slowing it down. The fluid phase’s temperature and velocity profiles are almost usually higher than those of the dust phase. The outcomes contribute to a better understanding of the two-phase theory’s fluid flow phenomenon.

Electrophoresis analysis of a hydrophobic spherical particle in a micropolar electrolyte solution

AbstractThe general expression for the time‐independent electrophoretic velocity of a spherical colloidal particle with a slippage surface in a microstructure electrolyte solution is derived. The two extreme cases of nonconducting and perfect conducting particles are investigated. The derived expression is valid for arbitrary Debye length and low particle zeta potentials. The concept of velocity spin slip is incorporated with the usual velocity slip at the particle's surface. The effect of the microstructure of fluid particles on the electrophoresis phenomena is discussed based on a micropolar fluid model. The influences of velocity slip and velocity spin slip are shown through various plots of electrophoretic velocity. The limiting case of electrolyte viscous solution is recovered. The principal findings of this research can be summarized as follows: As the micropolarity parameter increases, the normalized electrophoretic velocity decreases and reaches its peak in the case of Newtonian fluids. Additionally, the velocity slip acts as a counteracting factor that promotes an increase in the electrophoretic velocity. In the context of nonconducting particles, the normalized electrophoretic velocity rises as the spin slip parameter and Debye length decrease. Conversely, for perfectly conducting particles, it increases as the spin slip parameter and Debye length increase.

A novel technique to analyze the fractional model of Williamson and Casson non-Newtonian boundary layer flow

PurposeThe current analysis produces the fractional sample of non-Newtonian Casson and Williamson boundary layer flow considering the heat flux and the slip velocity. An extended sheet with a nonuniform thickness causes the steady boundary layer flow’s temperature and velocity fields. Our purpose in this research is to use Akbari Ganji method (AGM) to solve equations and compare the accuracy of this method with the spectral collocation method.Design/methodology/approachThe trial polynomials that will be utilized to carry out the AGM are then used to solve the nonlinear governing system of the PDEs, which has been transformed into a nonlinear collection of linked ODEs.FindingsThe profile of temperature and dimensionless velocity for different parameters were displayed graphically. Also, the effect of two different parameters simultaneously on the temperature is displayed in three dimensions. The results demonstrate that the skin-friction coefficient rises with growing magnetic numbers, whereas the Casson and the local Williamson parameters show reverse manners.Originality/valueMoreover, the usefulness and precision of the presented approach are pleasing, as can be seen by comparing the results with previous research. Also, the calculated solutions utilizing the provided procedure were physically sufficient and precise.

Dissipative MHD flow of ternary‐hybrid nanofluid over an inclined stretching sheet with heat source and mass flux due to temperature gradient

AbstractAn analysis has been made to illuminate the unsteady MHD slip flow of ternary‐hybrid nanofluid of water conveying spherical Cu, cylindrical Al2O3, and platelet Ag nanoparticles over an inclined stretching sheet. The above complex scenario explores how the presence of a magnetic field affects the behavior of ternary‐hybrid nanofluid over an inclined stretching surface. Understanding this interaction is crucial in advanced thermal systems like cooling mechanisms and energy generation technologies. The study can provide insights into optimizing heat transfer rates, enhancing thermal conductivity and improving efficiency in practical applications by manipulating the flow characteristics and temperature distribution in the system. The heat transfer has been analyzed incorporating Darcy dissipation and heat source in the presence of 1st order velocity slip. The presence of Soret effect makes the study more congenial. Using similarity transformation technique, the governing partial differential equations are converted into a system of ordinary differential equations. The reduced system is dealt with 4th order Runge–Kutta method with shooting technique. The comparison with earlier results gives a reliability of present results. The important findings are: velocity of the flow decelerates for higher values of 1st order slip parameter, velocity of the flow increases with increase in Soret number, increasing values of chemical reaction parameter lead to lower concentration in both the cases, that is, with or without velocity slip.

Flow separation and stability analysis for aligned magnetic field in a porous medium saturated by a titanium alloy nanofluid

ABSTRACT This article examines Joule heating and aligned magnetic field in a porous medium saturated by Ti-alloy nanofluid. The heat generation and first-order velocity slip towards an exponentially permeable shrinking surface are taken. Non-dimensional forms of the resulting flow equations are solved numerically for multiple solutions using the shooting technique along with the Runge–Kutta method of 4th order in MATLAB(R2021a). The stability of the resultant system of equations is verified through the smallest eigenvalue approach. Both the first and second solutions of correlation streamline profiles are extracted for appropriate values of physical parameters. By stability analysis, the first solution is unquestionably more stable than the second solution. The major outcome is that the Joule heating raises the fluid’s temperature. The presence of flow separation is identified in the shrinking regions and the delay of boundary layer separation is pointed out. These analyses play a significant role in the fields of aerodynamics, medicine, and space sciences.

Insight into the dynamics of slip and radiative effect on magnetohydrodynamic flow of hybrid ferroparticles over a porous deformable sheet

AbstractIn the present work, we explored the magnetohydrodynamic boundary layer flow in the presence of pressure gradient across a flat plate. The effects of the slip velocity conditions, thermal Radiation the addition of hybrid Ferroparticles (i.e., a mixture of two types of magnetic nanoparticles for example, (magnetite () and cobalt ferrite ()) in base fluid ( ) and Porous wall (suction/ injection) are also considered in this study. Basic partial differential equations are transformed into nonlinear ordinary differential equations using the appropriate similarity transformations. Then, this equation was treated numerically by using the Runge–Kutta–Fehlberg 4th–5th order method with the shooting technique and analytically via an efficient method called the Generalized Decomposition Method. The effects of various physical parameters on the velocity and temperature profiles are shown graphically. It is found that the incorporation of hybrid nanoparticles demonstrates a relatively substantial impact on the behavior of dynamic and thermal field; outperforming both non‐hybrid nanoparticles and regular fluid in terms of speed and temperature enhancement. The slip and permeability parameters significantly alter the flow structure. The positive values of the slip and permeability parameters enhance the flow velocity and reduce the temperature, leading to the desired flow behavior. Conversely, adopting negative values of these parameters reverses the effect. Furthermore, the radiation parameter enhances the temperature distribution. Additionally, the boundary layer separation tends to disappear with the increase in the magnetic parameter. The results obtained clearly show the accuracy of the proposed method and also indicate an excellent agreement between analytical and numerical data.

Vorticity dynamics at partial-slip boundaries

In this paper we discuss the dynamics of vorticity at partial-slip boundaries. We consider the total vector circulation, which includes both the total vorticity of the fluid and the slip velocity at the boundary (the interface vortex sheet). The generation of vector circulation is an inviscid process, which does not depend on either viscosity or the slip length at the boundary. Vector circulation is generated by the inviscid relative acceleration between the fluid and the solid, due to either tangential pressure gradients or tangential acceleration of the partial-slip wall. While the slip length does not affect the creation of vector circulation, it governs how vector circulation is distributed between the total vorticity of the fluid and the interface vortex sheet. Specifically, the partial-slip boundary condition prescribes the ratio between boundary vorticity and the strength of the interface vortex sheet, and the viscous boundary flux transfers vector circulation between the interface vortex sheet and the fluid interior to maintain this condition. The interaction between a vortex ring and a partial-slip wall is examined to highlight various aspects of this formulation. For the head-on collision, the quantity of vector circulation diffused into the fluid as secondary vorticity increases as the slip length is decreased, resulting in a stronger secondary vortex and increased rebound of the vortex ring. For the oblique interaction, the extent to which the vortex ring connects to the boundary increases as the slip length is increased.