scispace - formally typeset
Search or ask a question

Showing papers in "Applied Mathematics and Mechanics-english Edition in 2021"


Journal ArticleDOI
TL;DR: In this article, the entropy generation with heat and mass transfer in magnetohydrodynamic (MHD) stagnation point flow across a stretchable surface is examined, and numerical analysis of the resulting ODEs is carried out on the different flow parameters, and their effects on the rate of heat transport, friction drag, concentration, and entropy generation are considered.
Abstract: This work examines the entropy generation with heat and mass transfer in magnetohydrodynamic (MHD) stagnation point flow across a stretchable surface. The heat transport process is investigated with respect to the viscous dissipation and thermal radiation, whereas the mass transport is observed under the influence of a chemical reaction. The irreversibe factor is measured through the application of the second law of thermodynamics. The established non-linear partial differential equations (PDEs) have been replaced by acceptable ordinary differential equations (ODEs), which are solved numerically via the bvp4c method (built-in package in MATLAB). The numerical analysis of the resulting ODEs is carried out on the different flow parameters, and their effects on the rate of heat transport, friction drag, concentration, and the entropy generation are considered. It is determined that the concentration estimation and the Sherwood number reduce and enhance for higher values of the chemical reaction parameter and the Schmidt number, although the rate of heat transport is increased for the Eckert number and heat generation/absorption parameter, respectively. The entropy generation augments with boosting values of the Brinkman number, and decays with escalating values of both the radiation parameter and the Weissenberg number.

46 citations


Journal ArticleDOI
TL;DR: In this paper, the nonlinear dynamic responses of a functionally graded (FG) porous cylindrical shell embedded in elastic media are investigated, and an approximate analytical solution is obtained by using the multiple scales method.
Abstract: In this article, the nonlinear dynamic responses of sandwich functionally graded (FG) porous cylindrical shell embedded in elastic media are investigated. The shell studied here consists of three layers, of which the outer and inner skins are made of solid metal, while the core is FG porous metal foam. Partial differential equations are derived by utilizing the improved Donnell’s nonlinear shell theory and Hamilton’s principle. Afterwards, the Galerkin method is used to transform the governing equations into nonlinear ordinary differential equations, and an approximate analytical solution is obtained by using the multiple scales method. The effects of various system parameters, specifically, the radial load, core thickness, foam type, foam coefficient, structure damping, and Winkler-Pasternak foundation parameters on nonlinear internal resonance of the sandwich FG porous thin shells are evaluated.

38 citations


Journal ArticleDOI
TL;DR: In this article, an efficient method is developed to investigate the vibration and stability of moving plates immersed in fluid by applying the Kirchhoff plate theory and finite element method, which is considered as an ideal fluid and is described with Bernoulli's equation and the linear potential flow theory.
Abstract: An efficient method is developed to investigate the vibration and stability of moving plates immersed in fluid by applying the Kirchhoff plate theory and finite element method. The fluid is considered as an ideal fluid and is described with Bernoulli’s equation and the linear potential flow theory. Hamilton’s principle is used to acquire the dynamic equations of the immersed moving plate. The mass matrix, stiffness matrix, and gyroscopic inertia matrix are determined by the exact analytical integration. The numerical results show that the fundamental natural frequency of the submersed moving plates gradually decreases to zero with an increase in the axial speed, and consequently, the coupling phenomenon occurs between the first- and second-order modes. It is also found that the natural frequency of the submersed moving plates reduces with an increase in the fluid density or the immersion level. Moreover, the natural frequency will drop obviously if the plate is located near the rigid wall. In addition, the developed method has been verified in comparison with available results for special cases.

36 citations


Journal ArticleDOI
TL;DR: In this article, the impact of the Marangoni convention Casson nanoliquid flow under gyrotactic microorganisms over the porous sheet is investigated, where partial differential equations are re-structured into ordinary differential equations via suitable similar variables.
Abstract: Bioconvection research is primarily focused on the augmentation of energy and mass species, which has implications in the processes intensification, mechanical, civil, electronics, and chemical engineering branches. Advanced bioconvection technology sectors include cooling systems for electronic devices, building insulation, and geothermal nuclear waste disposal. Hence, the present investigation is mainly discoursing the impact of Marangoni convention Casson nanoliquid flow under gyrotactic microorganisms over the porous sheet. The partial differential equations (PDEs) are re-structured into ordinary differential equations (ODEs) via suitable similar variables. These ODEs are numerically solved with the help of the spectral relaxation method (SRM). The numerical outcomes are illustrated graphically for various parameters over velocity, temperature, concentration, and bioconvection profiles. Three-dimensional (3D) views of important engineering parameters are illustrated for various parameters. The velocity of the Casson nanoliquid increases with increasing the Marangoni parameter but decreases against higher porosity parameter. The surface drag force enhances for enhancement in the Marangoni number. The rate of mass transmission is higher for reaction rate constraint but diminishes for activation energy parameter. The higher radiative values augment the rate of heat transmission.

30 citations


Journal ArticleDOI
TL;DR: In this article, the size-dependent nonlinear thermal postbuckling characteristics of a porous functionally graded material (PFGM) microplate with a central cutout with various shapes using isogeometric numerical technique incorporating non-uniform rational B-splines were presented.
Abstract: This study presents the size-dependent nonlinear thermal postbuckling characteristics of a porous functionally graded material (PFGM) microplate with a central cutout with various shapes using isogeometric numerical technique incorporating non-uniform rational B-splines. To construct the proposed non-classical plate model, the nonlocal strain gradient continuum elasticity is adopted on the basis of a hybrid quasi-three-dimensional (3D) plate theory under through-thickness deformation conditions by only four variables. By taking a refined power-law function into account in conjunction with the Touloukian scheme, the temperature-porosity-dependent material properties are extracted. With the aid of the assembled isogeometric-based finite element formulations, nonlocal strain gradient thermal postbuckling curves are acquired for various boundary conditions as well as geometrical and material parameters. It is portrayed that for both size dependency types, by going deeper in the thermal postbuckling domain, gaps among equilibrium curves associated with various small scale parameter values get lower, which indicates that the pronounce of size effects reduces by going deeper in the thermal postbuckling regime. Moreover, we observe that the central cutout effect on the temperature rise associated with the thermal postbuckling behavior in the presence of the effect of strain gradient size and absence of nonlocality is stronger compared with the case including nonlocality in absence of the strain gradient small scale effect.

28 citations


Journal ArticleDOI
TL;DR: In this article, the system of equations determining the linear thermoelastic deformations of dielectrics within the recently called Moore-Gibson-Thompson (MGT) theory is considered.
Abstract: We consider the system of equations determining the linear thermoelastic deformations of dielectrics within the recently called Moore-Gibson-Thompson (MGT) theory. First, we obtain the system of equations for such a case. Second, we consider the case of a rigid solid and show the existence and the exponential decay of solutions. Third, we consider the thermoelastic case and obtain the existence and the stability of the solutions. Exponential decay of solutions in the one-dimensional case is also recalled.

26 citations


Journal ArticleDOI
TL;DR: In this article, a multi-resonator coupled metamaterials (MRCMs) with local resonators are proposed to obtain the multiple and wide band gaps, and the boundary conditions of the unit cell are obtained with Bloch's theorem.
Abstract: In this study, multi-resonator coupled metamaterials (MRCMs) with local resonators are proposed to obtain the multiple and wide band gaps. Kinetic models of the MRCMs are established, and the boundary conditions of the unit cell are obtained with Bloch’s theorem. The effects of structural parameters, including the mass of the resonator and the spring stiffness, on the distributions of the band gaps are studied. Furthermore, the frequency domain responses and the time domain responses are calculated for analyzing the structural vibration characteristics and the effects of damping on structural vibration. The results show that the frequency domain response can accurately express the distributions of the band gaps of the MRCMs, and we can increase the number and the width of the band gaps by using the MRCMs for the superior vibration suppression capability.

26 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of electromagneto-hydrodynamics, Hall currents, and convective and slip boundary conditions on the peristaltic propulsion of nanofluids through porous symmetric microchannels are explored.
Abstract: This study explores the effects of electro-magneto-hydrodynamics, Hall currents, and convective and slip boundary conditions on the peristaltic propulsion of nanofluids (considered as couple stress nanofluids) through porous symmetric microchannels. The phenomena of energy and mass transfer are considered under thermal radiation and heat source/sink. The governing equations are modeled and non-dimensionalized under appropriate dimensionless quantities. The resulting system is solved numerically with MATHEMATICA (with an in-built function, namely the Runge-Kutta scheme). Graphical results are presented for various fluid flow quantities, such as the velocity, the nanoparticle temperature, the nanoparticle concentration, the skin friction, the nanoparticle heat transfer coefficient, the nanoparticle concentration coefficient, and the trapping phenomena. The results indicate that the nanoparticle heat transfer coefficient is enhanced for the larger values of thermophoresis parameters. Furthermore, an intriguing phenomenon is observed in trapping: the trapped bolus is expanded with an increase in the Hartmann number. However, the bolus size decreases with the increasing values of both the Darcy number and the electroosmotic parameter.

23 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of nanoparticles on the thermodynamics of the Reiner-Rivlin nanomaterial, which also includes a temperaturedependent heat source (THS) and an exponential space-dependent heat sources (ESHS), was analyzed numerically.
Abstract: The thermodynamic features of the Reiner-Rivlin nanoliquid flow induced by a spinning disk are analyzed numerically. The non-homogeneous two-phase nanofluid model is considered to analyze the effect of nanoparticles on the thermodynamics of the Reiner-Rivlin nanomaterial, which also includes a temperature-dependent heat source (THS) and an exponential space-dependent heat source (ESHS). Further, the transfer of heat and mass is analyzed with velocity slip, volume fraction jump, and temperature jump boundary conditions. The finite difference method-based routine is used to solve the complicated differential equations formed after using the von-Karman similarity technique. Limiting cases of the present problem are found to be in good agreement with benchmarking studies. The relationship of the pertinent parameters with the heat and mass transport is scrutinized using correlation, which is further evaluated based on the probable error estimates. Multivariable models are fitted for the friction factor at the disk and heat transport, which accurately predict the dependent variables. The Reiner-Rivlin nanoliquid temperature is influenced comparatively more by the ESHS than by the THS. The Nusselt number is decreased by the ESHS and THS, whereas the friction factor at the disk is predominantly decremented by the wall roughness aspect. The increment in the non-Newtonian characteristic of the liquid leads more fluid to drain away in the radial direction far from the disk compared with the fluid nearby the disk in the presence of the centrifugal force during rotation. The increased thermal and volume fraction slip lowers the nanoliquid temperature and nanoparticle volume fraction profiles.

22 citations


Journal ArticleDOI
TL;DR: In this paper, the size-dependent geometrically nonlinear harmonically soft excited oscillation of composite truncated conical microshells (CTCMs) made of functionally graded materials (FGMs) integrated with magnetostrictive layers is analyzed.
Abstract: The size-dependent geometrically nonlinear harmonically soft excited oscillation of composite truncated conical microshells (CTCMs) made of functionally graded materials (FGMs) integrated with magnetostrictive layers is analyzed. It is supposed that the FGM CTCMs are subjected to mechanical soft excitations together with external magnetic fields. An analytical framework is created by a microstructure-dependent shell model having the 3rd-order distribution of shear deformation based on the modified couple stress (MCS) continuum elasticity. With the aid of the discretized form of differential operators developed via the generalized differential quadrature technique, a numerical solution methodology is introduced for obtaining the couple stress-based amplitude and frequency responses related to the primary resonant dynamics of the FGM CTCMs. Jump phenomena due to the loss of the first stability branch and falling down to the lower stable branch can be seen in the nonlinear primary resonance of the FGM CTCMs. It is demonstrated that the hardening type of nonlinearity results in bending the frequency response to the right side, and the MCS type of size effect weakens this pattern. Moreover, for higher material gradient indexes, the hardening type of nonlinearity is enhanced, and the MCS-based frequency response bends more considerably to the right side.

22 citations


Journal ArticleDOI
TL;DR: In this paper, a model of the partial differential expressions is altered into the forms of the ordinary differential equations via similarity transformations, and the obtained equations are numerically solved by a shooting scheme in the MAPLE software.
Abstract: Time-dependent, two-dimensional (2D) magnetohydrodynamic (MHD) micropolar nanomaterial flow over a shrinking/stretching surface near the stagnant point is considered. Mass and heat transfer characteristics are incorporated in the problem. A model of the partial differential expressions is altered into the forms of the ordinary differential equations via similarity transformations. The obtained equations are numerically solved by a shooting scheme in the MAPLE software. Dual solutions are observed at different values of the specified physical parameters. The stability of first and second solutions is examined through the stability analysis process. This analysis interprets that the first solution is stabilized and physically feasible while the second one is un-stable and not feasible. Furthermore, the natures of various physical factors on the drag force, skin-friction factor, and rate of mass and heat transfer are determined and interpreted. The micropolar nanofluid velocity declines with a rise in the suction and magnetic parameters, whereas it increases by increasing the unsteadiness parameter. The temperature of the micropolar nanofluid rises with increase in the Brownian motion, radiation, thermophoresis, unsteady and magnetic parameters, but it decreases against an increment in the thermal slip constraint and Prandtl number. The concentration of nanoparticles reduces against the augmented Schmidt number and Brownian movement values but rises for incremented thermophoresis parameter values.

Journal ArticleDOI
TL;DR: In this article, two different nanoparticles, namely, MoS2 and MgO, are suspended into the base-fluid to illustrate the Darcy flow and melting heat transmission in micropolar liquid.
Abstract: This article intends to illustrate the Darcy flow and melting heat transmission in micropolar liquid. The major advantage of micropolar fluid is the liquid particle rotation through an independent kinematic vector named the microrotation vector. The novel aspects of the Cattaneo-Christov (C-C) heat flux and Joule heating are incorporated in the energy transport expression. Two different nanoparticles, namely, MoS2 and MgO, are suspended into the base-fluid. The governing partial differential equations (PDEs) of the prevailing problem are slackening into ordinary differential expressions (ODEs) via similarity transformations. The resulting mathematical phenomenon is illustrated by the implication of fourth-fifth order Runge-Kutta-Fehlberg (RKF) scheme. The fluid velocity and temperature distributions are deliberated by using graphical phenomena for multiple values of physical constraints. The results are displayed for both molybdenum disulphide and magnesium oxide nanoparticles. A comparative benchmark in the limiting approach is reported for the validation of the present technique. It is revealed that the incrementing material constraint results in a higher fluid velocity for both molybdenum disulphide and magnesium oxide nanoparticle situations.

Journal ArticleDOI
Abstract: The magnetohydrodynamic Sutterby fluid flow instigated by a spinning stretchable disk is modeled in this study. The Stefan blowing and heat and mass flux aspects are incorporated in the thermal phenomenon. The conventional models for heat and mass flux, i.e., Fourier and Fick models, are modified using the Cattaneo-Christov (CC) model for the more accurate modeling of the process. The boundary layer equations that govern this problem are solved using the apt similarity variables. The subsequent system of equations is tackled by the Runge-Kutta-Fehlberg (RKF) scheme. The graphical visualizations of the results are discussed with the physical significance. The rates of mass and heat transmission are evaluated for the augmentation in the pertinent parameters. The Stefan blowing leads to more species diffusion which in turn increases the concentration field of the fluid. The external magnetism is observed to decrease the velocity field. Also, more thermal relaxation leads to a lower thermal field which is due to the increased time required to transfer the heat among fluid particles. The heat transport is enhanced by the stretching of the rotating disk.

Journal ArticleDOI
TL;DR: In this article, the nonlocal generalized thermoelastic theory for the formulation of an FGM microbeam is adopted in order to capture the size-dependent effect and the thermal wave effect.
Abstract: In extreme heat transfer environments, functionally graded materials (FGMs) have aroused great concern due to the excellent thermal shock resistance. With the development of micro-scale devices, the size-dependent effect has become an important issue. However, the classical continuum mechanical model fails on the micro-scale due to the influence of the size-dependent effect. Meanwhile, for thermoelastic behaviors limited to small-scale problems, Fourier’s heat conduction law cannot explain the thermal wave effect. In order to capture the size-dependent effect and the thermal wave effect, the nonlocal generalized thermoelastic theory for the formulation of an FGM microbeam is adopted in the present work. For numerical validation, the transient responses for a simply supported FGM microbeam heated by the ramp-type heating are considered. The governing equations are formulated and solved by employing the Laplace transform techniques. In the numerical results, the effects of the ramp-heating time parameter, the nonlocal parameter, and the power-law index on the considered physical quantities are presented and discussed in detail.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the heat and mass transfer of an Eyring-Powell fluid in a porous channel and showed the effects of the fluid parameters on the velocity, the temperature, the entropy generation, and the Bejan number.
Abstract: The unavailability of wasted energy due to the irreversibility in the process is called the entropy generation. An irreversible process is a process in which the entropy of the system is increased. The second law of thermodynamics is used to define whether the given system is reversible or irreversible. Here, our focus is how to reduce the entropy of the system and maximize the capability of the system. There are many methods for maximizing the capacity of heat transport. The constant pressure gradient or motion of the wall can be used to increase the heat transfer rate and minimize the entropy. The objective of this study is to analyze the heat and mass transfer of an Eyring-Powell fluid in a porous channel. For this, we choose two different fluid models, namely, the plane and generalized Couette flows. The flow is generated in the channel due to a pressure gradient or with the moving of the upper lid. The present analysis shows the effects of the fluid parameters on the velocity, the temperature, the entropy generation, and the Bejan number. The nonlinear boundary value problem of the flow problem is solved with the help of the regular perturbation method. To validate the perturbation solution, a numerical solution is also obtained with the help of the built-in command NDSolve of MATHEMATICA 11.0. The velocity profile shows the shear thickening behavior via first-order Eyring-Powell parameters. It is also observed that the profile of the Bejan number has a decreasing trend against the Brinkman number. When ηi → 0 (i = 1, 2, 3), the Eyring-Powell fluid is transformed into a Newtonian fluid.

Journal ArticleDOI
TL;DR: In this paper, the peristaltic flow of a heated Jeffrey fluid inside a duct with an elliptic cross-section is studied, and a thorough heat transfer mechanism is interpreted by analyzing the viscous effects in the energy equation.
Abstract: The peristaltic flow of a heated Jeffrey fluid inside a duct with an elliptic cross-section is studied. A thorough heat transfer mechanism is interpreted by analyzing the viscous effects in the energy equation. The governing mathematical equations give dimensionless partial differential equations after simplification. The final simplified form of the mathematical equations is evaluated with respect to the relevant boundary conditions, and the exact solution is attained. The results are further illustrated by graphs, and the distinct aspects of peristaltic flow phenomena are discussed.

Journal ArticleDOI
TL;DR: In this article, the authors analyze the unsteady Maxwell hybrid nanofluid toward a stretching/shrinking surface with thermal radiation effect and heat transfer, and the results reveal that the skin friction coefficient increases by adding nanoparticles and suction parameters.
Abstract: The non-Newtonian fluid model reflects the behavior of the fluid flow in global manufacturing progress and increases product performance. Therefore, the present work strives to analyze the unsteady Maxwell hybrid nanofluid toward a stretching/shrinking surface with thermal radiation effect and heat transfer. The partial derivatives of the multivariable differential equations are transformed into ordinary differential equations in a specified form by applying appropriate transformations. The resulting mathematical model is clarified by utilizing the bvp4c technique. Different control parameters are investigated to see how they affect the outcomes. The results reveal that the skin friction coefficient increases by adding nanoparticles and suction parameters. The inclusion of the Maxwell parameter and thermal radiation effect both show a declining tendency in the local Nusselt number, and as a result, the thermal flow efficacy is reduced. The reduction of the unsteadiness characteristic, on the other hand, considerably promotes the improvement of heat transfer performance. The existence of more than one solution is proven, and this invariably leads to an analysis of solution stability, which validates the first solution viability.

Journal ArticleDOI
TL;DR: In this paper, the ill-posed issue (i.e., excessive mandatory boundary conditions (BCs) cannot be met simultaneously) exists not only in strain-driven nonlocal models but also in stress-driven ones.
Abstract: Due to the conflict between equilibrium and constitutive requirements, Eringen’s strain-driven nonlocal integral model is not applicable to nanostructures of engineering interest. As an alternative, the stress-driven model has been recently developed. In this paper, for higher-order shear deformation beams, the ill-posed issue (i.e., excessive mandatory boundary conditions (BCs) cannot be met simultaneously) exists not only in strain-driven nonlocal models but also in stress-driven ones. The well-posedness of both the strain- and stress-driven two-phase nonlocal (TPN-StrainD and TPN-StressD) models is pertinently evidenced by formulating the static bending of curved beams made of functionally graded (FG) materials. The two-phase nonlocal integral constitutive relation is equivalent to a differential law equipped with two restriction conditions. By using the generalized differential quadrature method (GDQM), the coupling governing equations are solved numerically. The results show that the two-phase models can predict consistent scale-effects under different supported and loading conditions.

Journal ArticleDOI
TL;DR: Based on the dynamic k-equation large-eddy simulation (LES), this method uses a precursor method to generate atmospheric inflow turbulence, models the tower and nacelle wakes, and improves the body force projection method based on an anisotropic Gaussian distribution function as mentioned in this paper.
Abstract: In a large wind farm, the wakes of upstream and downstream wind turbines can interfere with each other, affecting the overall power output of the wind farm. To further improve the numerical accuracy of the turbine wake dynamics under atmosphere turbulence, this work proposes some improvements to the actuator line-large-eddy simulation (AL-LES) method. Based on the dynamic k-equation large-eddy simulation (LES), this method uses a precursor method to generate atmospheric inflow turbulence, models the tower and nacelle wakes, and improves the body force projection method based on an anisotropic Gaussian distribution function. For these three improvements, three wind tunnel experiments are used to validate the numerical accuracy of this method. The results show that the numerical results calculated in the far-wake region can reflect the characteristics of typical onshore and offshore wind conditions compared with the experimental results. After modeling the tower and nacelle wakes, the wake velocity distribution is consistent with the experimental result. The radial migration velocity of the tip vortex calculated by the improved blade body force distribution model is 0.32 m/s, which is about 6% different from the experimental value and improves the prediction accuracy of the tip vortex radial movement. The method proposed in this paper is very helpful for wind turbine wake dynamic analysis and wind farm power prediction.

Journal ArticleDOI
TL;DR: In this paper, the effects of the constituent materials, background field, and coil size on the quench and mechanical behavior of high temperature superconducting coils were analyzed using axisymmetric electro-magneto-thermal models.
Abstract: Quench and mechanical behaviors are critical issues in high temperature superconducting coils. In this paper, the quench characteristics in the rare earth barium copper oxide (REBCO) pancake coil at 4.2 K are analyzed, and a two-dimensional (2D) axisymmetric electro-magneto-thermal model is presented. The effects of the constituent materials, background field, and coil size are analyzed. An elastoplastic mechanical model is used to study the corresponding mechanical responses during the quench propagation. The variations of the temperature and strain in superconducting layers are compared. The results indicate that the radial strain evolutions can reflect the transverse quench propagation and the tensile hoop and radial stresses in superconducting layers increase with the quench propagation. The possible damages are discussed with the consideration of the effects of the background field and coil size. It is concluded that the high background field significantly increases the maximum tensile hoop and radial stresses in quenching coils and local damage may be caused.

Journal ArticleDOI
TL;DR: In this paper, the heat transfer of the combined magnetohydrodynamic (MHD) and electroosmotic flow (EOF) of non-Newtonian fluid in a rotating microchannel is analyzed.
Abstract: The heat transfer of the combined magnetohydrodynamic (MHD) and electroosmotic flow (EOF) of non-Newtonian fluid in a rotating microchannel is analyzed. A couple stress fluid model is scrutinized to simulate the rheological characteristics of the fluid. The exact solution for the energy transport equation is achieved. Subsequently, this solution is utilized to obtain the flow velocity and volume flow rates within the flow domain under appropriate boundary conditions. The obtained analytical solution results are compared with the previous data in the literature, and good agreement is obtained. A detailed parametric study of the effects of several factors, e.g., the rotational Reynolds number, the Joule heating parameter, the couple stress parameter, the Hartmann number, and the buoyancy parameter, on the flow velocities and temperature is explored. It is unveiled that the elevation in a couple stress parameter enhances the EOF velocity in the axial direction.

Journal ArticleDOI
TL;DR: In this paper, the heat transfer rate of the thermal Marangoni convective flow of a hybrid nanomaterial is optimized by using the response surface methodology (RSM) in the presence of a variable inclined magnetic field, thermal radiation, and an exponential heat source.
Abstract: The heat transfer rate of the thermal Marangoni convective flow of a hybrid nanomaterial is optimized by using the response surface methodology (RSM). The thermal phenomenon is modeled in the presence of a variable inclined magnetic field, thermal radiation, and an exponential heat source. Experimentally estimated values of the thermal conductivity and viscosity of the hybrid nanomaterial are utilized in the calculation. The governing intricate nonlinear problem is treated numerically, and a parametric analysis is carried out by using graphical visualizations. A finite difference-based numerical scheme is utilized in conjunction with the 4-stage Lobatto IIIa formula to solve the nonlinear governing problem. The interactive effects of the pertinent parameters on the heat transfer rate are presented by plotting the response surfaces and the contours obtained from the RSM. The mono and hybrid nanomaterial flow fields are compared. The hybrid nanomaterial possesses enhanced thermal fields for nanoparticle volume fractions less than 2%. The irregular heat source and the thermal radiation enhance the temperature profiles. The high level of the thermal radiation and the low levels of the exponential heat source and the angle of inclination (of the magnetic field) lead to the optimized heat transfer rate (Nux = 7.462 75).

Journal ArticleDOI
TL;DR: In this article, a mathematical model linking thermoelasticity to photothermal experiments is proposed with the consideration of the photothermal effect, and the system equations for coupled plasma, heat conduction with phase-lags (PLs), and motion equations are introduced and solved by using the Laplace transform technique.
Abstract: A mathematical model linking thermoelasticity to photothermal experiments is proposed with the consideration of the photothermal effect. The system equations for coupled plasma, heat conduction with phase-lags (PLs), and motion equations are introduced and solved by using the Laplace transform technique. The photothermal, thermal, and elastic waves in a rotating solid cylinder of semiconductor material are analyzed with the proposed model. The cylinder surface is constrained and subjected to a time-dependent pulse heat flux. The sensitivity of the physical fields for the angular velocity, PLs, and thermal vibration parameters is investigated. In addition, the effects of the effective parameters on the physical quantities are graphically illustrated and discussed in detail.

Journal ArticleDOI
TL;DR: In this article, the first-order shear deformation theory (FSDT) is used to establish a nonlinear dynamic model for a conical shell truncated by a functionally graded graphene platelet-reinforced composite (FG-GPLRC).
Abstract: In this study, the first-order shear deformation theory (FSDT) is used to establish a nonlinear dynamic model for a conical shell truncated by a functionally graded graphene platelet-reinforced composite (FG-GPLRC). The vibration analyses of the FG-GPLRC truncated conical shell are presented. Considering the graphene platelets (GPLs) of the FG-GPLRC truncated conical shell with three different distribution patterns, the modified Halpin-Tsai model is used to calculate the effective Young’s modulus. Hamilton’s principle, the FSDT, and the von-Karman type nonlinear geometric relationships are used to derive a system of partial differential governing equations of the FG-GPLRC truncated conical shell. The Galerkin method is used to obtain the ordinary differential equations of the truncated conical shell. Then, the analytical nonlinear frequencies of the FG-GPLRC truncated conical shell are solved by the harmonic balance method. The effects of the weight fraction and distribution pattern of the GPLs, the ratio of the length to the radius as well as the ratio of the radius to the thickness of the FG-GPLRC truncated conical shell on the nonlinear natural frequency characteristics are discussed. This study culminates in the discovery of the periodic motion and chaotic motion of the FG-GPLRC truncated conical shell.

Journal ArticleDOI
TL;DR: In this paper, the characteristics of the heat transport mechanism in an annulus filled with the Ag-MgO/H2O hybrid nanoliquid under the influence of quadratic thermal radiation, nonlinear convection, and temperature-dependent heat source/sink parameter were analyzed.
Abstract: The convective heat transfer of hybrid nanoliquids within a concentric annulus has wide engineering applications such as chemical industries, solar collectors, gas turbines, heat exchangers, nuclear reactors, and electronic component cooling due to their high heat transport rate. Hence, in this study, the characteristics of the heat transport mechanism in an annulus filled with the Ag-MgO/H2O hybrid nanoliquid under the influence of quadratic thermal radiation and quadratic convection are analyzed. The non-uniform heat source/sink and induced magnetic field mechanisms are used to govern the basic equations concerning the transport of the composite nanoliquid. The dependency of the Nusselt number on the effective parameters (thermal radiation, nonlinear convection, and temperature-dependent heat source/sink parameter) is examined through sensitivity analyses based on the response surface methodology (RSM) and the face-centered central composite design (CCD). The heat transport of the composite nanoliquid for the space-related heat source/sink is observed to be higher than that for the temperature-related heat source/sink. The mechanisms of quadratic convection and quadratic thermal radiation are favorable for the momentum of the nanoliquid. The heat transport rate is more sensitive towards quadratic thermal radiation.

Journal ArticleDOI
TL;DR: In this paper, a mathematical model for nonlocal vibration and buckling of embedded two-dimensional (2D) decagonal quasicrystal (QC) layered nanoplates is proposed.
Abstract: A mathematical model for nonlocal vibration and buckling of embedded two-dimensional (2D) decagonal quasicrystal (QC) layered nanoplates is proposed. The Pasternak-type foundation is used to simulate the interaction between the nanoplates and the elastic medium. The exact solutions of the nonlocal vibration frequency and buckling critical load of the 2D decagonal QC layered nanoplates are obtained by solving the eigensystem and using the propagator matrix method. The present three-dimensional (3D) exact solution can predict correctly the nature frequencies and critical loads of the nanoplates as compared with previous thin-plate and medium-thick-plate theories. Numerical examples are provided to display the effects of the quasiperiodic direction, length-to-width ratio, thickness of the nanoplates, nonlocal parameter, stacking sequence, and medium elasticity on the vibration frequency and critical buckling load of the 2D decagonal QC nanoplates. The results show that the effects of the quasiperiodic direction on the vibration frequency and critical buckling load depend on the length-to-width ratio of the nanoplates. The thickness of the nanoplate and the elasticity of the surrounding medium can be adjusted for optimal frequency and critical buckling load of the nanoplate. This feature is useful since the frequency and critical buckling load of the 2D decagonal QCs as coating materials of plate structures can now be tuned as one desire.

Journal ArticleDOI
TL;DR: In this article, a microstructure-based constitutive model and molecular dynamics (MD) simulation were used to investigate the unique mechanical behavior of FeCoCrNiCu HEAs during the indentation.
Abstract: High entropy alloys (HEAs) attract remarkable attention due to the excellent mechanical performance. However, the origins of their high strength and toughness compared with those of the traditional alloys are still hardly revealed. Here, using a microstructure-based constitutive model and molecular dynamics (MD) simulation, we investigate the unique mechanical behavior and microstructure evolution of FeCoCrNiCu HEAs during the indentation. Due to the interaction between the dislocation and solution, the high dislocation density in FeCoCrNiCu leads to strong work hardening. Plentiful slip systems are stimulated, leading to the good plasticity of FeCoCrNiCu. The plastic deformation of FeCoCrNiCu is basically affected by the motion of dislocation loops. The prismatic dislocation loops inside FeCoCrNiCu are formed by the dislocations with the Burgers vectors of $${a \over 6}\left[ {\bar 11\bar 2} \right]$$ and $${a \over 6}\left[ {1\bar 12} \right]$$ , which interact with each other, and then emit along the 〈111〉 slip direction. In addition, the mechanical properties of FeCoCrNiCu HEA can be predicted by constructing the microstructure-based constitutive model, which is identified according to the evolution of the dislocation density and the stress-strain curve. Strong dislocation strengthening and remarkable lattice distortion strengthening occur in the deformation process of FeCoCrNiCu, and improve the strength. Therefore, the origins of high strength and high toughness in FeCoCrNiCu HEAs come from lattice distortion strengthening and the more activable slip systems compared with Cu. These results accelerate the discovery of HEAs with excellent mechanical properties, and provide a valuable reference for the industrial application of HEAs.

Journal ArticleDOI
TL;DR: In this article, the entropy analysis of a non-Newtonian tangent hyperbolic material flow through a vertical microchannel with a quadratic density temperature fluctuation is performed.
Abstract: In many industrial applications, heat transfer and tangent hyperbolic fluid flow processes have been garnering increasing attention, owing to their immense importance in technology, engineering, and science. These processes are relevant for polymer solutions, porous industrial materials, ceramic processing, oil recovery, and fluid beds. The present tangent hyperbolic fluid flow and heat transfer model accurately predicts the shear-thinning phenomenon and describes the blood flow characteristics. Therefore, the entropy production analysis of a non-Newtonian tangent hyperbolic material flow through a vertical microchannel with a quadratic density temperature fluctuation (quadratic/nonlinear Boussinesq approximation) is performed in the present study. The impacts of the hydrodynamic flow and Newton’s thermal conditions on the flow, heat transfer, and entropy generation are analyzed. The governing nonlinear equations are solved with the spectral quasi-linearization method (SQLM). The obtained results are compared with those calculated with a finite element method and the bvp4c routine. In addition, the effects of key parameters on the velocity of the hyperbolic tangent material, the entropy generation, the temperature, and the Nusselt number are discussed. The entropy generation increases with the buoyancy force, the pressure gradient factor, the non-linear convection, and the Eckert number. The non-Newtonian fluid factor improves the magnitude of the velocity field. The power-law index of the hyperbolic fluid and the Weissenberg number are found to be favorable for increasing the temperature field. The buoyancy force caused by the nonlinear change in the fluid density versus temperature improves the thermal energy of the system.

Journal ArticleDOI
TL;DR: In this article, a linear coupling spring is installed between two parallel nonlinear energy sink (NEs) to expand the application scope of such vibration absorbers, and the performance of the parallel and parallel-coupled NESs and the system response induced by the coupling spring are compared.
Abstract: Nonlinear energy sink (NES) can passively absorb broadband energy from primary oscillators. Proper multiple NESs connected in parallel exhibit superior performance to single-degree-of-freedom (SDOF) NESs. In this work, a linear coupling spring is installed between two parallel NESs so as to expand the application scope of such vibration absorbers. The vibration absorption of the parallel and parallel-coupled NESs and the system response induced by the coupling spring are studied. The results show that the responses of the system exhibit a significant difference when the heavier cubic oscillators in the NESs have lower stiffness and the lighter cubic oscillators have higher stiffness. Moreover, the e±ciency of the parallel-coupled NES is higher for medium shocks but lower for small and large shocks than that of the parallel NESs. The parallel-coupled NES also shows superior performance for medium harmonic excitations until higher response branches are induced. The performance of the parallel-coupled NES and the SDOF NES is compared. It is found that, regardless of the chosen SDOF NES parameters, the performance of the parallel-coupled NES is similar or superior to that of the SDOF NES in the entire force range.

Journal ArticleDOI
TL;DR: In this paper, the leaderless and leader-following finite-time consensus problems for multi-agent systems (MASs) described by first-order linear hyperbolic partial differential equations (PDEs) are studied.
Abstract: The leaderless and leader-following finite-time consensus problems for multi-agent systems (MASs) described by first-order linear hyperbolic partial differential equations (PDEs) are studied. The Lyapunov theorem and the unique solvability result for the first-order linear hyperbolic PDE are used to obtain some sufficient conditions for ensuring the finite-time consensus of the leaderless and leader-following MASs driven by first-order linear hyperbolic PDEs. Finally, two numerical examples are provided to verify the effectiveness of the proposed methods.