Unsteady Fluid Flow Research Articles

Theoretical Survey of Time-Dependent Micropolar Nanofluid Flow over a Linear Curved Stretching Surface

The heat and mass transfer of the unsteady flow of a micropolar fluid over a curved stretching surface was considered in this study. The Brownian motion and thermophoresis effects were explored in this analysis. The effects of suction/injection cases on the curved surface were discussed. Under flow assumptions, a mathematical model was designed employing boundary layer approximations using partial differential equations. A suitable transformation was developed using the lie symmetry method. Partial differential equations were transformed into ordinary differential equations by suitable transformations. The dimensionless system was elucidated through a numerical technique, namely bvp4c. The involved physical parameters’ influences are described in the form of graphs as well as numerical results in the form of tables. Our current work is helpful in the engineering and industrial fields. The unsteadiness parameter increases which Nusselt number at increased but concentrations declined. The thermophoresis parameter increases when increasing the Nusselt number because the small number of nanoparticles enhances the heat transfer rate. The temperature profile declined due to increasing values of unsteadiness parameter for both cases of suction and injection cases.

Koo and Kleinstreuer–Li correlation and modified Buongiorno model on unsteady radiative non-Newtonian fluid flow

This research paper investigates the heat and mass transport characteristics in an unsteady flow of Maxwell nanofluid (NF). While examining heat transfer properties, thermal radiation is taken into account. Further, copper oxide with water-based NF is considered. The mass transfer and effective thermal conductivity of nanofluid flow are scrutinized by Koo and Kleinstreuer–Li (KKL) NF model. Through apt transformations, relevant flow expressions are converted to ordinary differential equations (ODEs). The numerical approach Runge–Kutta–fourth–fifth Fehlberg’s order process (RKF-45) algorithm with shooting technique is utilized to solve the generated ODEs. Results reveal that, the rise in values of unsteadiness parameter has a positive impact on both concentration and thermal profiles. The Deborah number has constructive impact on heat transport and reverse influence on velocity field. The improved heat transport is seen for augmented values of radiation and heat source/sink parameters. The Brownian motion parameter has positive influence on heat transport and reverse effect on mass transport.

A Prabhakar fractional approach with generalized fourier law for thermal activity of non-newtonian second-grade type fluid flow: a fractional approach

In this work, we studied the unsteady and incompressible flow of second-grade MHD fluid moving on a vertical oscillating plate, which is passing under the possessions of an applied inclined magnetic field. The non-dimensional governed equations are turned into a fractional model using the most advanced and effective fractional definition, Prabhakar fractional derivative, which is frequently based on generalized Fourier's and Fick's laws. The resultant system is handled using integral transform, i.e. the Laplace transformation (LT) scheme, and some numerical methods are also applied for the Laplace inverse. The graphical and numerical representation of all parameters is also deliberated to analyze the physical behavior of the effects of significant parameters. As a result, it concluded that the impact of the second-grade fluid constraint slowed down the momentum profile of the moving fluid. Furthermore, in comparing the velocity field attained by our applied fractional scheme with existing literature, the overlapping of both curves with each other indicates the validity of our attained results of momentum profile. Additionally, the overlapping of both numerical scheme curves for the Laplace inverse also verifies the study's findings.

Heat transfer analysis in three-dimensional unsteady magnetic fluid flow of water-based ternary hybrid nanofluid conveying three various shaped nanoparticles: A comparative study

The heat transport analysis in the three-dimensional unsteady flow of non-Newtonian nanofluid is studied in this research communication. Comparison of water-based ternary hybrid nanofluid conveying three various shaped nanoparticles (titanium spherical-carbon nanotube (CNT) cylindrical-graphene platelet) and Zinc Oxide-Society of Automotive Engineers 50 nanolubricant (ZnO-SAE50Nanolubricant) is emphasized with two different models. Also, this paper is mainly focused on an electrically non-conducting and incompressible magnetic liquid with moderate saturation magnetization and low Curie temperature. An infinitely long, straight wire delivering an electric current generates a magnetic field that affects the fluid. To study heat transfer characteristics thermal radiation is taken into account. Pertinent flow expressions are reduced into ordinary differential equations (ODEs) through appropriate transformations. The obtained ODEs are solved by means of the numerical method Runge–Kutta–Fehlberg’s fourth-fifth order method (RKF-45) with shooting technique. Results reveals that the ZnO-SAE50Nanolubricant flow shows maximum heat transport followed by titanium spherical-CNT cylindrical-graphene platelet-water hybrid nanofluid flow for increased values of radiation parameter. Further in this scenario, it is found that the heat transfer rate in ternary hybrid nanofluid increases about 2–5% whereas in Nanolubricant it is about 3–8% for the gradual increasing values of the ferromagnetic interaction parameter.

Unsteady MHD free convection flow of an exothermic fluid in a convectively heated vertical channel filled with porous medium

Utilizing porous media in a new mathematical model to improve convective heat transfer characteristics in a variety of applications, such as radiation nuclear disposal storing, evaporation cooling, sieving, geological extraction, crude petroleum refining, and building heating and cooling, is becoming increasingly important. This study proposed a numerical analysis of the unsteady magnetohydrodynamic free convection flow of an exothermic fluid with Newtonian heating. This discovery reveals two types of solutions: steady state and unsteady state. After transforming the governing equation from dimensional form to dimensionless form, the steady state governing equation was solved by the Homotopy Perturbation Method. However, the implicit finite difference approach is used to solve the time-dependent governing equations numerically. The impact of various emerging parameters, namely the Hartmann number, Boit number, Darcy number, Navier slip parameter, and the Frank-Kamenetskii parameter, was discussed and graphically analyzed. During the computations and analysis, it was discovered that a minor rise in the Hartman number results in the Lorentz force, which streamlines the momentum barrier layer and hence slows the fluid flow. The fluid velocity, on the other hand, rose as the porous medium, thermal Biot number, slip parameter, and temperature field increased as the viscous reactive fluid parameter and Newtonian heating increased. The skin friction and Nusselt number were also examined and reported. By comparing the finding to an existing work, a great agreement was revealed.

Entropy generation analysis in an unsteady hydromagnetic micropolar fluid flow along an exponentially stretchable sheet with slip properties

ABSTRACT This present study communicates entropy generation analysis in an unsteady flow of a reactive hydromagnetic micropolar fluid passing an exponentially stretchable sheet with multiple slip properties. The developed model scrutinizes the impacts of varying viscosity alongside with non-uniform heat source coupled with nonlinear thermal radiation. The formulated nonlinear equations describing the problem are carefully transformed into ordinary differential equations via similar transformations approach, while the solutions to the modified equations are sought using the Galerkin weighted residual method. A strong relationship exists between the results obtained in this study with the related published ones in literature in some limiting conditions. The current investigation reveals that the dimensionless velocity, temperature and concentration profiles depreciate with the unsteadiness parameter, whereas the micropolar material term accelerates the velocity profiles. Besides, the analysis shows that the hydrodynamic slip parameter improves heat and mass transfer irreversibilities while growth in the material micropolar term, Eckert and Prandtl numbers cause a rise in the entropy generation in the system.

UNSTEADY MHD FLOW OF NON -NEWTONIAN FLUID WITH MASS TRANSFER IN A HORIZONTAL CHANNEL

This study analyzes the unsteady MHD flow of non-Newtonian fluid in horizontal channel. The upper plate is oscillating and moving while the bottom plate is stationary. Solutions for momentum, energy and concentration equation are obtained by the He-Laplace scheme. The effect of various flow parameters controlling the physical situation is discussed with the aid of graphs. Significant results from this study, shows that velocity and concentric fields decrease with the increase in chemical reaction parameter

Unsteady nonisothermal tangent hyperbolic fluid flow in a stenosed blood vessel with pulsatile pressure gradient and body acceleration

Unsteady nonisothermal tangent hyperbolic fluid flow in a stenosed blood vessel with pulsatile pressure gradient and body acceleration

Simulation of unsteady MHD flow of incompressible fluid between two parallel plates using Laplace-Adomian decomposition method

The aim of this study is to numerically obtain the solution to an unsteady incompressible fluid confined between two parallel plates with constant velocity. The nonlinear partial differential equation governing the flow is first converted to a nonlinear ordinary differential equation using similarity transformation and solved using the combination of Laplace transform and Adomian decomposition method (LADM). The model parameters affecting the flow geometry is analysed and presented in tables and graphs. The method produces an accurate, elegant, computable, and approximately convergent solution which gives great insight but with less mathematical sophistication.

Simulation of unsteady MHD flow of incompressible fluid between two parallel plates using Laplace-Adomian decomposition method

Simulation of unsteady MHD flow of incompressible fluid between two parallel plates using Laplace-Adomian decomposition method

Unsteady Flow of an MHD Tangent Hyperbolic Nanofluid Over a Stretching Sheet

Abstract The recent article addresses the unsteady flow of MHD incompressible tangent hyperbolic fluid with Nanofluid particles in the direction of a stretching surface. Nano-fluid is related to thermo-phoretic and Brownian movement. With proper help through the transformation procedure, the set of non-linear (PDEs) is re-framed into (ODEs). The initiate expressions of momentum, temperature field, and nano-particle concentration are composed into groups of nonlinear equations. That consequential terminology is computed shooting system. The impact of fundamental parameters on the flow field, thermal circulation, and meditation is described. Moreover, the flow field behavior due to the Wall friction, local Nusselt, and Sherwood numbers are examined. This study is significant as this transformation determined the shooting technique’s numerical result and ensured the physical parameters’ behavior graphically. The results show that the velocity field diminishes by escalating the Weissenberg (We) figure and power-law index (n), while thermal and concentration fields remain to detect elevating at similar parameters. Furthermore, the computed result is compared with existing literature and gets accuracy.

Pulsatile Flow Through a Curved Pipe – An Analytical Study

In this paper, the unsteady flow of Newtonian fluid through a curved pipe due to a pulsatile pressure gradient has been considered. The flow is three dimensional and the partial differential equations governing the flow are highly coupled and non-linear. Approximate analytical solutions of the governing partial differential equations have been obtained without neglecting any term containing the curvature ratio. Perturbation series in terms of curvature ratio has been used for obtaining the solutions. It is interesting to note that the solutions are valid for large as well as small values of Womersley number. The effect of different parameters such as, Reynolds number, Womersley number and curvature ratio on the flow through curved pipe is discussed in this paper. It is found that the axial velocity is qualitatively periodic in nature, as expected. The Reynolds number and curvature ratio are found to shift the axial velocity towards the outer boundary of the curved pipe.

Magnetofluid unsteady electroosmotic flow of Jeffrey fluid at high zeta potential in parallel microchannels

Abstract In this article, the magnetofluid unsteady electroosmotic flow (EOF) of Jeffrey fluid with high zeta potential is studied by using the Chebyshev spectral method and the finite difference method. By comparing the potential distribution and velocity distribution obtained by the Chebyshev spectral method and finite difference method, it is concluded that the Chebyshev spectral method has higher precision and less computation. Then the numerical solution obtained by the Chebyshev spectral method is used to analyze the flow characteristics of Jeffrey fluid at high zeta potential. The results show that the velocity of Jeffrey fluid increases with the increase of the wall zeta potential and electric field intensity. The oscillation amplitude of velocity distribution increases with the increase of relaxation time, but decreases with the increase of retardation time. With the increase of Hartmann number, the velocity first increases and then decreases. The positive pressure gradient promotes the flow of fluid, and the reverse pressure gradient impedes the flow of fluid.

Unsteady MHD free convective flow past a moving vertical plate in a porous medium with radiation and chemical reaction including arbitrary thermal and solutal ramped condition

AbstractThe motive behind this investigation is to examine the unsteady magnetohydrodynamics free convective fluid flow with heat and mass transfer of a viscous, incompressible flow past a moving upright plate in a porous medium with radiation, chemical reaction, arbitrary thermal, and solutal ramped condition. An analytical solution for momentum, energy, and concentration equations is accomplished by implementing the Laplace transformation technique. The influence of different nondimensional parameters on fluid velocity, temperature, and concentration along with skin friction and rate of heat transfer as well as mass transfer at the plate are exhibited graphically. It can be spotted that both the concentration and temperature field decrease for rising values of the ramped parameter, radiation parameter, chemical reaction parameter, and Schmidt number. Moreover, it is detected that the fluid velocity drops in the case of the isothermal plate, and velocity upsurges for the ramped plate temperature. Investigation simulates that the rate of heat transfer, as well as rate of mass transfer, is escalated on hiking radiation parameter.

Peristaltic mechanism of hydromagnetic Jeffrey fluid having variable thermal conductivity and slip conditions

In this study, we focus on the slip effects on the peristaltic unsteady flow of magnatohydromagnetic Jeffrey fluid in a flow passage with non-conducting and flexible boundary walls. The effect of the magnetic field with varying thermal conductivity is taken under the influence of heat transfer analysis. The dimensionless system of PDEs is solved analytically, and the obtained results are computed for the temperature, pressure drop, the axial pressure gradient, axial velocity, and then these results are discussed for different values of the physical parameters of our interest. For the stream functions, the contour plots are also obtained which indicates the exact flow behavior within the flow channel, and the effects of the physical parameters on Jeffery fluid within the flow channel are discussed briefly. Our results indicate that the heat transfer coefficient decreases with an increase in thermal slip and velocity slip parameters. Furthermore, it shows that the size of the trapped bolus is greater for the inclined magnetic field as compared to the transverse magnetic field.

New Dimensionless Number for the Transition from Viscous to Turbulent Flow

Within the framework of Classical Continuum Thermomechanics, we consider an unsteady isothermal flow of a simple isotropic linear viscous fluid in the liquid state to investigate the transient flow conditions. Despite the attention paid to this problem by several research works, it seems that the understanding of turbulence in these flow conditions is controversial. We propose a dimensionless procedure that highlights some aspects related to the transition from viscous to turbulent flow which occurs when a finite amplitude pressure wave travels through the fluid. This kind of transition is demonstrated to be described by a (first) dimensionless number, which involves the bulk viscosity. Furthermore, in the turbulent flow regime, we show the role played by a (second) dimensionless number, which involves the turbulent bulk viscosity, in entropy production. Within the frame of the 1D model, we test the performance of the dimensionless procedure using experimental data on the pressure waves propagation in a long pipe (water hammer phenomenon). The obtained numerical results show good agreement with the experimental data. The results’ inspection confirms the predominant role of the turbulent bulk viscosity on energy dissipation processes.

Unsteady MHD Flow through Porous Media with Temporal Variation in Temperature and Concentration at the Plate

The present analysis aims at to the free convective unsteady MHD flow of a viscous fluid through a saturated porous medium, considering the radiative heat loss and chemical reaction of the diffusing species in the presence of an exponential time varying cross flow. The novelties of the present analysis are that the electrically conducting fluid is made to flow through saturated porous medium subjected to transverse magnetic field; the presence of constant volumetric heat source acts as an internal thermal power within the boundary layer; the principle of superposition underlying basis of method of analytical solution. Some important findings of the study are that the flow model acts as a surface-coolant and it lowers down the bounding surface-concentration also; the imposed magnetic field, thermal radiation, porosity of the saturated porous medium and the destructive chemical reaction of the diffusing species have effects on progressive thinning of the boundary layer.

NUMERICAL STUDY OF THE INFLUENCE OF TEMPERATURE-DEPENDENT VISCOSITY ON THE UNSTEADY LAMINAR FLOW AND HEAT TRANSFER OF A VISCOUS INCOMPRESSIBLE FLUID DUE TO A ROTATING DISC

In this article, the effect of temperature-dependent viscosity (TVD) on the unsteady laminar flow and heat transfer (HT) of a viscous incompressible fluid due to a rotating disc (RD) has been investigated numerically by exploiting an in-house numerical code. A set of time-dependent, axisymmetric, and non-linear partial differential equations which govern the fluid flows and heat transfer are reduced to non-linear local non-similarity ordinary differential equations by introducing a newly developed group of transformations for different time regimes. Three different solution methods, such as, (i) perturbation solution method for small t, (ii) asymptotic solution method for large t, and (iii) implicit finite difference method for the entire t regime, have been applied to solve the resulting equations treating t as the time-dependent rotating parameter. The local radial skin friction, tangential skin friction and the heat transfer are computed at the surface of the disc for different numerical parameters, such as, Prandtl number, Pr and the viscosity-variation parameter, e. Besides, the key dimensionless quantities such as velocity and temperature profiles, which are inherently linked with the boundary layer thickness, are presented graphically for different values of e while Pr = 0.72. It is found that the dimensionless radial, tangential and axial velocity profiles decrease as e increases, and consequently, the momentum boundary layer thickness is decreased. On the other hand, the non-dimensional temperature profiles are increased owing to the increasing values of e, and this effect eventually leads to a small increment in the thermal boundary layer thickness.

Chemical reaction with aligned magnetic field effects on unsteady MHD Kuvshinski fluid flow past an inclined porous plate in the presence of radiation and Soret effects

AbstractThe present paper studies the effect of a chemical reaction and aligned magnetic field on an unsteady magnetohydrodynamic free convection Kuvshinski fluid flow past an inclined plate through a porous medium in the presence of Soret and radiation. The plate is assumed to be embedded in a uniform porous medium and moves with a constant velocity in the flow direction in the presence of a transverse magnetic field. The systems of nondimensional governing linear partial differential equations are solved analytically by using the perturbation technique. The influences of various nondimensional parameters on the velocity, the temperature, and the concentration are discussed, as also the effects of various parameters on the skin‐friction coefficient and the rate of heat transfer in the form of Nusselt number and rate of mass transfer in the form of Sherwood number at the surface. Velocity distribution is observed to increase with an increase in viscoelastic parameter and Soret parameter, whereas it shows reverse effects in the case of the aligned magnetic field, inclined parameter, magnetic parameter, the temperature diminishes with the increase of radiation parameter and heat absorption parameter.

Computational analysis on unsteady hydromagnetic Couette flow of fluid—Particle suspension in an accelerated porous channel

In this analysis, Semi-analytical solution representing the time dependent Couette flow of conducting fluid–particle suspension in a permeable channel is offered in the existence of a magnetic field. The magnetic field is anticipated to be positioned either with the conducting suspension or the velocity of the magnetic field is same with the moving wall. Solution to the dimensionless coupled equations are provided by adopting the well known Laplace transform technique and D’Alermbert Method for both flow cases. The obtained solutions are later inverted to the time domain with the help of the Riemann sum approximation. Numerical values for fluid–particle suspension was validated with existing benchmark. Expressions for fluid–particle velocity and their corresponding skin fiction are also found in both cases. Influence of a number of flow parameters on flow formation are demonstrated via graphs. Results indicate that, irrespective of the magnetic field positioned either with the conducting suspension or with the moving wall, injection velocity strengthens the momentum boundary layer yielding an increase in fluid phase velocity and particle phase velocity, whereas the contrast is true with suction.