Nonlinear Slip Research Articles

Truth in Time Travel: Subversions of Time in An Adventure

This article explores how Frances Lamont and Elizabeth Morison’s An Adventure (1913) disrupts temporal and spatial dichotomies through its supposed representations of time travel. An Adventure presents time as a shifting force that aligns with Bergsonian notions of temporality – specifically the concepts of objective and subjective time as defined in Henri Bergson’s Creative Evolution (1911) and “Time and Free Will” (1913). This article also considers how Freudian notions of “condensation” further outline the subjective rendering of time in An Adventure’s surreal journeys back in time to the French Revolution and how the narrative’s subjective presentation of time aligns with Ford Madox Ford’s later theories of literary impressionism, particularly his idea that modernist narratives are composed of “various unordered pictures”. This article ultimately argues that Lamont and Morison’s book benefited from the temporally minded scientific and social climate of the time and used the theoretical groundwork of thinkers like Henri Bergson, Ford Madox Ford and Sigmund Freud as starting points from which they could tell their tale as truth. Specifically, their formal construction of the text as scientific research seeks to consciously obscure the differentiation between fact and fable, effectively positing their nonlinear time slip as truth. If that truth is humored, Lamont and Morison are proposing a more radical conception of time than Bergson – a nonlinear conception of time – a proposition that sits in tension with their use of scientific diction and discourse.

Analysis of the bending performance of unbonded flexible risers

ABSTRACT As the key equipment for offshore oil and gas production systems, the unbonded flexible riser (UFR) is subjected to extensive interlayer and intralayer non-linear contact and slip that make it difficult to analyse its bending performance. In this paper, by combining the theoretical model of bending of the UFR with the finite element model, the influence of the number, width, external pressure and coefficient of friction of tensile armour wires on its bending performance was studied. The results showed that the non-slip bending stiffness of the UFR decreased by 3.20 and 23.35 kN·m2 every time one of the outer tensile armour wires was removed and the width of the wires was reduced by 0.3 mm, respectively. The external pressure and coefficient of friction did not influence its bending stiffness in the non-slip and complete slip stages, and were linearly related to the curvature of the critical slip.

Mixed Convection Flow of MHD Casson Nanofluid over a Vertically Extending Sheet with Effects of Hall, Ion Slip and Nonlinear Thermal Radiation

This manuscript investigates the effects of viscous dissipation, Ohmic heating, nonlinear thermal radiation, chemical reactions, Hall current, and ion slip on the mixed convection flow of magnetohydrodynamic (MHD) Casson nanofluid over a vertically stretching sheet in a spongy medium. The strongly nonlinear ordinary differential equations (ODEs) derived from the governing equations are solved using a sixth-order, seven-stage Runge–Kutta (RK6) method in conjunction with the shooting technique. Numerical simulations are conducted using an open-source Python programming language. The study evaluates temperature, velocity, nanoparticle concentration, skin friction coefficients, Nusselt number (rate of heat transfer), and Sherwood number (rate of mass transfer) based on dimensionless parameters. Key findings reveal that increasing ion slip and Hall currents enhance the velocity profile in the x-direction, while the Casson parameter exerts a diminishing effect. The fluid temperature decreases with higher Hall current, Casson parameter, and ion slip values but increases due to nonlinear thermal radiation, the temperature ratio parameter, and the Eckert number. Furthermore, the chemical reaction parameter and Schmidt number reduce nanoparticle concentration within the boundary layer, with the Casson parameter amplifying this effect. The study also examines the rates of mass, heat, and momentum transfer near the surface under varying parameter influences, presenting results through comprehensive graphs and tables. To validate the numerical method, a comparative analysis is conducted against previous studies, demonstrating excellent agreement and thus confirming the reliability and accuracy of the computational approach.

Stabilised finite element method for Stokes problem with nonlinear slip condition

This work introduces a stabilised finite element formulation for the Stokes flow problem with a nonlinear slip boundary condition of friction type. The boundary condition is enforced with the help of an additional Lagrange multiplier representing boundary traction and the stabilised formulation is based on simultaneously stabilising both the pressure and the traction. We establish the stability and the a priori error analyses, and perform a numerical convergence study in order to verify the theory.

A Priori Error Analysis and Finite Element Approximations for a Coupled Model Under Nonlinear Slip Boundary Conditions

A Priori Error Analysis and Finite Element Approximations for a Coupled Model Under Nonlinear Slip Boundary Conditions

Analytical Solution for Bending Deformation of Steel–Concrete Composite Beams Considering Nonlinear Interfacial Slip

Analytical Solution for Bending Deformation of Steel–Concrete Composite Beams Considering Nonlinear Interfacial Slip

Application of Convolutional Networks for Localization and Prediction of Scalar Parameters of Fractured Geological Inclusion

Seismic inversion is an important part of the modern geological exploration process. Novel applications of deep learning are capable of handling heterogeneous media, but require too much data for training. In this paper, we focus on the prediction of fracture inclusion location and its parameters in rock media and approach the problem in the multi-task manner. For this, several multi-task convolutional neural network (CNN) architectures are proposed and compared. The direct seismic problem is considered in the heterogeneous fractured geological model based on the well-known Marmousi2 model in a two-dimensional case. The model of the deformable solid medium containing slip planes with nonlinear slip conditions on them and explicit–implicit numerical method is applied to obtain the synthetic seismic dataset for CNN training and validation.

A portable and integrated traveling-wave electroosmosis microfluidic pumping system driven by triboelectric nanogenerator

The lab-on-a-chip system can simultaneously complete the preparation, reaction, separation, and detection of samples on a centi-scale platform by manipulating trace fluids. Traveling-wave electroosmosis (TWEO) technology, with the merit of electric signal-based flexible control over the fluid behavior, can achieve precise driving of fluids, which is an important requirement of the lab-on-a-chip system. However, the peripheral power equipment such as the function generator required for TWEO limits the application in some occasions lacking power supply facilities, due to its large size and high cost. In this paper, we have developed a brand-new portable and integrated TWEO microfluidic pumping system, wherein a front-end module of triboelectric nanogenerator (TENG) is in serial connection with the back-end microfluidic pumping chip, which greatly improves portability and reduces costs. The TENG can output stable four consecutively 90°-phase-shifted alternating current voltage signals in a continuous rotational motion originated by its novel electrode structure. And the four-phase traveling potential waves are applied to four sets of electrode strips alternately distributed in the microchannel, thereby inducing nonlinear electroosmotic slip on the electrode surface, achieving stable pumping of fluids in the microchannel. Compared with traditional fluid-driven methods, this system features high safety for the operator and chip but also realizes the almost instantaneous start, stop, and directional switching in response to a turn on, turn off, and turn in reverse of TENG, respectively. Finally, this system is integrated into a droplet microfluidic chip for the efficient generation of single emulsion droplets. This study presents a promising solution for the miniaturization, integration, and commercialization of lab-on-a-chip system.

Enhanced transport phenomena in Casson fluid flow over radiative moving surface: Influence of velocity and thermal slip conditions with mixed convection and chemical reaction

Researchers are interested in the non-Newtonian fluid flow with mixed convection because of its extensive use in industry and manufacturing. Additionally, thermal radiation in convective heat transfer is critical for thermal transmission regulation. As a result, the authors provide an in-depth study of how mixed convective effects on concentration and temperature impact mass, heat, and non-Newtonian Casson fluid flow. A transverse magnetic field and vertical permeable stretched sheet affect the fluid. Nonlinear thermal radiation, Brownian motion, thermophoresis, velocity slip, and temperature slip are all examined. The governing nonlinear partial differential equations (PDEs) can be changed into especially nonlinear coupled ordinary differential equations (ODEs) with the right similarity transformation. We use the RK-45 technique in Mathematica to solve the system to accommodate different physical attributes. The data are analyzed graphically. This study shows that increasing the free convection parameters [Formula: see text] and [Formula: see text] improves the velocity profile. However, the Casson parameter, magnetic field, velocity slip, and mass suction parameter lower it. Increasing [Formula: see text], and [Formula: see text] parameters lead to a higher temperature profile, whereas [Formula: see text], and [Formula: see text] parameters have the opposite. Increased concentration is shown with [Formula: see text] and [Formula: see text] parameters, whereas [Formula: see text] and [Formula: see text] have the opposite impact. Skin friction increases against [Formula: see text] and [Formula: see text] and reduces for S and M Heat transfer increases for [Formula: see text] and S whereas reduces for [Formula: see text] and [Formula: see text] Mass transfer increases for [Formula: see text] and [Formula: see text] and reduces for [Formula: see text] and [Formula: see text].

Optimizing entropy in mixed convective MHD dissipative nanofluid with cross-diffusion and nonlinear velocity slip

Entropy optimization is crucial for enhancing fluid dynamics and heat transfer, leading to improved efficiency, energy conservation, and environmental sustainability. Recognizing its significance, we examine the influence of radiation, Joule heating, heat sources, mixed convection, and nonlinear slip on the entropy-optimized flow of a dissipative nanofluid over a curved surface. To seamlessly integrate within the MATLAB bvp4c framework, we convert the set of multi-order ODEs, derived from fundamental PDEs via a similarity transformation approach, into a system of first-order ODEs. Graphs and analytical discussions are used to evaluate the parameters of the problem. The velocity within the boundary layer, along with entropy, experiences reduction due to the enhancement in both first- and second-order slip velocity parameters, as well as curvature parameters. The temperature plot improves with the increase in parameters such as the Soret number and Dufour number, as well as radiation. Conversely, the temperature plot reduces with the rise in suction values. The study indicates that a higher Brinkman number is associated with a lower Bejan number, while the first- and second-order velocity slip parameters have a contrasting effect, leading to an increase in the Bejan number.

Overlapping Grid-Based Spectral Collocation Technique for Bioconvective Flow of MHD Williamson Nanofluid over a Radiative Circular Cylindrical Body with Activation Energy

The amalgamation of motile microbes in nanofluid (NF) is important in upsurging the thermal conductivity of various systems, including micro-fluid devices, chip-shaped micro-devices, and enzyme biosensors. The current scrutiny focuses on the bioconvective flow of magneto-Williamson NFs containing motile microbes through a horizontal circular cylinder placed in a porous medium with nonlinear mixed convection and thermal radiation, heat sink/source, variable fluid properties, activation energy with chemical and microbial reactions, and Brownian motion for both nanoparticles and microbes. The flow analysis has also been considered subject to velocity slips, suction/injection, and heat convective and zero mass flux constraints at the boundary. The governing equations have been converted to a non-dimensional form using similarity variables, and the overlapping grid-based spectral collocation technique has been executed to procure solutions numerically. The graphical interpretation of various pertinent variables in the flow profiles and physical quantities of engineering attentiveness is provided and discussed. The results reveal that NF flow is accelerated by nonlinear thermal convection, velocity slip, magnetic fields, and variable viscosity parameters but decelerated by the Williamson fluid and suction parameters. The inclusion of nonlinear thermal radiation and variable thermal conductivity helps to enhance the fluid temperature and heat transfer rate. The concentration of both nanoparticles and motile microbes is promoted by the incorporation of activation energy in the flow system. The contribution of microbial Brownian motion along with microbial reactions on flow quantities justifies the importance of these features in the dynamics of motile microbes.

Numerical investigation on MHD non-Newtonian pulsating Fe 3 O 4-blood nanofluid flow through vertical channel with nonlinear thermal radiation, entropy generation, and Joule heating

The main aim of the present investigation is to examine the effect of nonlinear thermal radiation, slip, and Joule heating on MHD Pulsatile flow of third-grade ferro-nanofluid via vertical channel with entropy generation. The significance of this study is that it has plenty of physiological applications like cancer treatment, vitamin injections, dialysis, heart–lung machines during surgeries and industrial applications like filtration, pharmaceutical fluid production, and dispensing cosmetic/glue emulsions with no contamination. Furthermore, the ferro-nanoliquid model is the best model for numerous bio/industrial fluids. Therefore, this study explores the entropy analysis of pulsating third-grade ferro-nanoliquid flow between two parallel vertical walls under an applied magnetic field. Blood is taken as a base fluid (third grade), and iron oxide is used as nanoparticles. The governed nonlinear partial differential equations (PDEs) are nondimensionalized, and then the perturbation technique is employed to attain the set of nonlinear ordinary differential equations (ODEs). The bvp4c technique with MATLAB software is utilized to obtain the solutions for the set of ODEs. The deviations in several physical quantities on the flow variables are deployed via graphs. An increment in Eckert number and radiation parameter accelerates the temperature. Entropy generation rate and Bejan number are accelerated for greater values of radiation parameter. The values of the skin friction and Nusselt number against various physical parameters are presented in tables.

Efficiency assessment of thermal radiation utilizing flow of advanced nanocomposites on riga plate

Utilizing nanostructured materials to optimize thermal processes for renewable energy is an important strategy that has been applied in numerous engineering disciplines for diverse interventions such as photovoltaic thermal systems. Ternary nanofluids have demonstrated potential for improving the cooling capabilities of this kind of system. The current research focuses on enhancing the thermal performance of convective flow of a water-based trihybrid nanofluid across a Riga plate incorporating carbon nanotubes in spherical, graphene in cylindrical and Al2O3 in platelet shapes. Several mechanisms like non-linear heat production, thermal radiation, velocity and thermal slip conditions have all been investigated regarding the flow describing equations. Due to the high complexity of the problem modeling and numerical methods, conventional techniques to the parametric work that incorporate various model factors can fail to derive accurate solutions. This study assesses the ability of soft computing techniques to determine the behavior of a problem with various connected parameters to resolve this issue. With help from numerical scheme Lobatto IIIa technique reference data, the artificial neural network is trained. Furthermore, a constructive technique using artificial neural networks (Levenberg–Marquardt) is used to quantitatively determine the rate of heat transmission on the surface of Riga plates. With the use of correlation, fitting analysis, regression, mean squared error, absolute error, and error histogram, the prediction performance of the proposed algorithms is examined. The Cfx and Nux reach convergence with mean squared errors close to 10−8 and 10−10 after 626 and 100 epochs. The investigation illustrates the benefits of using soft computing methods to accurately investigate the behavior of complex flow models. The most important discovery is that, in comparison to mono- and binary-hybrid nanofluids, ternary hybrid nanofluids have a greater thermal responsiveness.

Machine learning non-isothermal study of the blade coating process (NIS-BCP) using non-Newtonian nanofluid with magnetohydrodynamic (MHD) and slip effects

The underlying investigation reports the effects of the magnetohydrodynamics (MHD) and non-linear slip coefficients on the coating thickness of the web/substrate during the blade coating process. Two dimensional analysis of the blade coating process is performed using non-Newtonian nanofluid model with the help of basic equations of fluid dynamics are performed. Firstly, the system of equations of motion (EOM) is transformed into the non-dimensional form by using the scaling factors. Secondly, the modeled equations are further simplified with the help of lubrication approximation theory (LAT). The resulting boundary value problem is transformed into stream function to eliminate the pressure gradient from the flow equation and then numerically tackled with the Matlab built-in function bvp4c with the method of false position (Regula-Falsi Method). A comparative study of numerical data with results simulated by artificial neural networks (ANN) found that results are in excellent agreement. The impact of sundry parameters on physical quantities is examined through graphical representation. Results indicate that the influence of magnetohydrodynamics (MHD), nanoparticle and slip effects cannot be ignored during the blade coating flow, as a significant impact of these parameters is observed on velocity, temperature, pressure, coating thickness, blade load, and streamlines.

Toward a continuum description of lubrication in highly pressurized nanometer-wide constrictions: The importance of accurate slip laws.

The Reynolds lubrication equation (RLE) is widely used to design sliding contacts in mechanical machinery. While providing an excellent description of hydrodynamic lubrication, friction in boundary lubrication regions is usually considered by empirical laws, because continuum theories are expected to fail for lubricant film heights h0 ≪ 10 nm, especially in highly loaded tribosystems with normal pressures pn ≫ 0.1 GPa. Here, the performance of RLEs is validated by molecular dynamics simulations of pressurized (with pn = 0.2 to 1 GPa) hexadecane in a gold converging-diverging channel with minimum gap heights h0 = 1.4 to 9.7 nm. For pn ≤ 0.4 GPa and h0 ≥ 5 nm, agreement with the RLE requires accurate constitutive laws for pressure-dependent density and viscosity. An additional nonlinear wall slip law relating wall slip velocities to local shear stresses extends the RLE's validity to even the most severe loading condition pn = 1 GPa and h0 = 1.4 nm. Our results demonstrate an innovative route for continuum modeling of highly loaded tribological contacts under boundary lubrication.

Influence of non-linear slip dependent zeta potential on the bi-layered electrohydrodynamic flow in an electrically actuated microsystem

In this paper, the electro-osmotic flow (EOF) of two immiscible fluids through an electrically actuated micro-slit with a non-linear slip-dependent zeta potential is considered. The main objective of this work is to enhance the EOF velocity of non-polar fluid with an intensive flow variation in micro-confinements. We present the comparison between the Poisson–Nernst–Planck (P–N–P) and the Poisson–Boltzmann model and illustrate the impact of different parameters, such as Debye–Hückel parameter, slip coefficient, and interfacial potential drop, on the ionic concentration and the induced potential in detail. In this study, the interface between two immiscible fluids is considered to be planar, and a potential drop is observed close to the interface due to the development of back-to-back diffuse layers. At the interface between two layers, the continuity of the velocity and total stresses (Maxwell stress and shear stress) are taken into account to investigate the flow field in the system of immiscible electrolytes. The P–N–P model, linked with the ion transport equation and the Poisson equation, is employed to describe the motion of electrolyte solutions. The non-linear governing equations are numerically computed using a pressure-correction-based finite volume technique based on a staggered grid algorithm. Closed-form analytical solutions are derived for both steady and unsteady EOF field of two immiscible fluids for the low wall zeta potential and non-overlapping electrical double layer. The analytical solutions are well validated with our numerical results under suitable assumptions. It is also observed that the slip-dependent zeta potential successfully provides a considerable enhancement in EOF velocity over a broad range of parameters such as zeta potential, Debye–Hückel parameter, as well as boundary slip parameter. The results for both layers are highly affected by unequal wall potential, and the ion concentrations are highly actuated by the external electric field.

Heat transfer enhancement in engine oil based hybrid nanofluid through combustive engines: An entropy optimization approach

Engine oil based hybrid nanofluid flow past a non-linearly stretching surface is important in solar energy applications, combustive engines, heat exchangers and many other industrial sector machinery. In this study, engine oil based hybrid nanofluid is modeled with multi-walled carbon nanotubes and copper oxide nanoparticles to enhance the heat transfer phenomena, minimize the entropy generation and to obtain a theoretical model more aligned with experimental findings. Engine oil hybrid nanofluid is modeled with non-linear thermal slip case so that a comparative study for no slip, linear slip and non-linear thermal slip is presented in a broader scenario. A variable magnetic field is applied in perpendicular direction with heat source/sink effects. Similarity analysis is conducted to obtain a non-dimensional system of ordinary differential equations. In order to solve the obtained system, a modified homotopy analysis approach is proposed with least square and Galerkin optimizers. Results are validated through mean squared residual errors and comparison with existing experimental data in literature. Analysis on results is presented through 2D plots, bar plots and pie charts. Highest percentage rate of increase in heat transfer of engine oil is obtained to be 23.75% with increase in heat source when volume fraction of both copper oxide and multi-walled carbon nanotubes is 4%. Moreover, entropy in engine oil flow is optimized till zero at 1% volume fraction of copper oxide and 3% volume fraction of multi-walled carbon nanotube in first order thermal slip case. These results are useful in enhancing various physical and engineering properties of engine oil 10W40C by adding multi-walled carbon nanotubes and copper oxide nanoparticles.

A coupled model of the fluid flow with nonlinear slip Tresca boundary condition

In this article, we consider the finite element discretization of the time-dependent Stokes equations written under the Boussinesq approximation, coupled with the convection-diffusion equation and provided with Tresca's Friction Law. Existence and uniqueness of a solution are established. To solve Stokes variational inequality, we suggest an alternating direction method of multiplier. We derive some a priori estimates and validate the obtained theoretical results by numerical simulations.

An improved Klinkenberg permeability model for tight reservoir cores: Effects of non-linear gas slippage to real gases

Absolute permeability is one of the most fundamental reservoir-rock properties required for reservoir simulation models. Most research studies are focused on the Klinkenberg gas slippage, considering the ideal behavior of the flowing gas under first- and second-order slippage conditions. This paper assesses the non-linear slippage of real gas through the low permeability reservoir rock samples. The cubic equation of state (van der Waals/Soave-Redlich-Kwong/Peng-Robinson), coupled with Taylor series-based non-linear slippage, predicts the apparent permeability for the non-Darcy gas flow in tight reservoir rock. The novelty of the present contribution is to develop a comprehensive mathematical model to describe the temperature- and pressure-dependent non-linear slippage effect accounting for the real gas behavior, which is based on the fundamental principle of momentum balance. The thirty-nine sets of experimental results of different authors using different core samples (e.g., coal seams, tight sandstones, tight carbonates, gas-shale reservoirs) and gases (Air, H2, He, N2, CH4, C2H6, and CO2) are used to authenticate the proposed non-linear slip model for real gases. Results show that (a) the proposed model correctly predicts infinite permeability and non-linear slippage coefficients of eight-tests non-ideal gases with an average absolute deviation of ≤9.69%, (b) non-linear slippage dominates for the core samples having permeability <1.5 mD, and (c) the first- and second-order slippage coefficients vary from 0.76 to 6.22 atm and 0.15–9.30 atm2, respectively. The proposed model is simple and may readily be applied for the reservoir simulation of coal seams, tight sandstones, tight carbonates, gas-shale reservoirs, etc., for reservoir characterization, forecasting future natural gas production, decision-making, and efficient reservoir management practices for enhanced production efficiency and sustainability.

On Characterization of Shear Viscosity and Wall Slip for Concentrated Suspension Flows in Abrasive Flow Machining.

In the realm of abrasive flow machining (AFM), precise finishing and maintaining dimensional accuracy have remained challenging due to non-uniformities in the AFM process and complexities associated with the abrasive media's shear viscosity and wall slip behavior. By addressing these challenges, this study introduces a comprehensive framework, combining theoretical foundations, measurement techniques, and experimental setups. Utilizing capillary flow, a novel compensation strategy is incorporated within the Mooney method to counter entrance pressure drop effects. This enhanced capillary flow method emerges as a promising alternative to the conventional Cox-Merz empirical rule, enabling precise characterization of wall slip behavior and shear viscosity, particularly at elevated shear rates. The abrasive media exhibit a Navier nonlinear wall slip, as highlighted by the Mooney method. Rigorous verification of the proposed methodologies and models against supplemental experiments showcases a high degree of congruence between predicted and observed results, emphasizing their accuracy and broad application potential in AFM. This research illuminates the intricacies of the abrasive media's behavior, accentuating the need for meticulous characterization, and provides a robust foundation for genuine modeling and predictions in material removal within AFM.