Mathematical Problems in Engineering

Volume 2017 (2017), Article ID 1421862, 16 pages

https://doi.org/10.1155/2017/1421862

## Solution of the Fractional Form of Unsteady Squeezing Flow through Porous Medium

Department of Mathematics, Faculty of Science, Tanta University, Tanta 31527, Egypt

Correspondence should be addressed to A. A. Hemeda; moc.oohay@ademehaa

Received 21 March 2017; Revised 17 May 2017; Accepted 15 June 2017; Published 1 August 2017

Academic Editor: Mauro Gaggero

Copyright © 2017 A. A. Hemeda et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

#### Abstract

We propose two friendly analytical techniques called Adomian decomposition and Picard methods to analyze an unsteady axisymmetric flow of nonconducting, Newtonian fluid. This fluid is assumed to be squeezed between two circular plates passing through porous medium channel with slip and no-slip boundary conditions. A single fractional order nonlinear ordinary differential equation is obtained by means of similarity transformation with the help of the fractional calculus definitions. The resulting fractional boundary value problems are solved by the proposed methods. Convergence of the two methods’ solutions is confirmed by obtaining various approximate solutions and various absolute residuals for different values of the fractional order. Comparison of the results of the two methods for different values of the fractional order confirms that the proposed methods are in a well agreement and therefore they can be used in a simple manner for solving this kind of problems. Finally, graphical study for the longitudinal and normal velocity profiles is obtained for various values of some dimensionless parameters and fractional orders.

#### 1. Introduction

The importance of the fluid flow through a porous medium goes back a long time in various applications in life such as agriculture, industry, and oil and gas production, where the focus was on estimating and optimizing production. Similarly, another important application is the simulation of ground water pollution, mostly occurring due to leakage of chemicals from tanks and oil pipelines. The objective is to consider ground water as one medium and polluted water as another, so that the spreading in the latter medium and its consequences can be studied.

In recent times, after the introduction of the modified Darcy Law [1], analysis through a porous medium has advantage in an important topic for the research community such as reservoir, petroleum, chemical, civil, environmental, and agricultural and biomedical engineering. Some practical applications in these fields include chemical reactors, filtration, geothermal reservoirs, ground water hydrology, and drainage and recovery of crude oil from pores of reservoir rocks [2–7].

The importance of squeezing flow is due to its wide applications in many fields such as chemical, biomechanics, food industries, and mechanical and industrial engineering. Practical applications of squeezing flows in these fields are modeling of lubrication systems, polymer processing, compression and injection molding, and so on. These flows are induced by applying normal stresses or vertical velocities by means of a moving boundary, which can be frequently observed in various hydrodynamical tools and machines. Stefan [8] is one of the first researchers who operated on the development of squeezing flows and an ad hoc asymptotic solution to Newtonian fluids. In [9] Thorpe has established an explicit solution to the squeeze flow considering inertial terms. However, in [10], P. S. Gupta and A. S. Gupta proved that the solution given in [9] fails in satisfying boundary conditions. Verma in [11] and Singh et al. in [12] have presented numerical solutions for squeezing flow between parallel plates. Leider and Byron performed in [13] theoretical analysis of power-law fluid between parallel disks. The optimal homotopy asymptotic method (OHAM) has been used by Qayyum et al. [14] to analyze the unsteady axisymmetric flow of nonconducting Newtonian fluid squeezed between two circular plates with slip and no-slip boundaries. Also, the homotopy perturbation method (HPM) has been developed by Qayyum et al. [15], to model and analyze the unsteady axisymmetric flow of nonconducting, Newtonian fluid squeezed between two circular plates passing through a porous medium channel with slip boundary condition. The new iterative and Picard methods had been used by Hemeda and Eladdad in [16] for solving the fractional form of unsteady axisymmetric flow of a nonconducting, Newtonian fluid squeezed between two circular plates with slip and no-slip boundaries. For more studies on squeezing flow through porous medium and also for more theoretical and experimental studies on squeezing flow, you can see [17–25].

Fractional calculus becomes one of the important branches of applied mathematics that deals with derivatives and integrals of arbitrary orders. It is the generalized differential and integral calculus of an arbitrary order. Recently, it has the importance of many researchers because of its wide appearance in many applications in fluid mechanics, viscoelasticity, biology, physics, and engineering. Moreover, the ordinary differential operator is a local operator, but the fractional order differential operator is nonlocal. Consequently, attention has been given to the solutions of fractional differential equations for the most important fields of physics, fluid mechanics, and so on. The exact analytical solutions to most nonlinear fractional order problems cannot be found. Therefore, approximation and numerical techniques can be used. Picard method [26–29] and the Adomian decomposition method [30–34] are two powerful approaches of these techniques which can be used in simple manner and short time to obtain analytical approximations to nonlinear problems and they are particularly valuable as tools for researchers, because they provide immediate and visible symbolic terms of analytic solutions, as well as numerical approximate solutions to nonlinear differential equations without linearization or discretization.

In the last years, the applications of the proposed methods are extended to the fractional differential equations. Our objective of this article is to prepare and utilize the proposed methods to obtain an analytical solution to the fractional form of an unsteady axisymmetric flow of nonconducting, Newtonian fluid squeezed between two circular plates passing through porous medium with slip and no-slip boundary conditions. Validity of the two methods is confirmed by comparing the obtained results. In addition, the effects of various fractional order, constant containing permeability, Reynolds number, and slip parameter on the solution are studied tabularly and graphically.

#### 2. Formulation of the Problem

In this section, the unsteady axisymmetric squeezing flow of incompressible first-grade fluid with density , viscosity , and kinematic viscosity , squeezed between two circular plates having speed and passing through porous medium channel, is considered with a fractional order form. At any time , it is assumed that the distance between the two circular plates is . Also, it is assumed that -axis is the central axis of the channel while -axis is taken as normal to it. Plates move symmetrically with respect to the central axis while the flow is axisymmetric about . The longitudinal and normal velocity components in radial and axial directions are and , respectively. For more physical explanation, see [14–16].

The basic system of equations describing the motion of the fluid iswhere is the function of velocity, is the function of generalized pressure, and is the permeability constant.

The boundary values on and arewhere is the plates velocity. The boundary values in (2) are due to slipping at the upper plate when and symmetry at . If we introduce the dimensionless parameter (1) transforms toThe boundary conditions on and are The elimination of between (5) and (6) giveswhere is the Laplacian operator.

Defining the components of velocity as follows [10]:we see that (4) is identically satisfied and (8) becomeswhereIn the above equations and are functions of but, for similarity solution, we consider them as constants. Since , integrating first equation of (11), we getwhere and are constants. The plates move away from each other symmetrically with respect to when and . The squeezing flow exists when the plates approach each other when and From (11) and (12) it follows that . Then (10) becomesUsing (7) and (9), the boundary conditions in cases of no-slip and slip boundaries at the upper plate can be defined in the form:

#### 3. Fractional Calculus

In the following, we state some definitions of the fractional calculus, which can be used in this work.

*Definition 1. *The Riemann-Liouville fractional integral operator of order and of a function and is defined as follows [35]:Also, for , we can define

*Definition 2. *The fractional order derivative of in the Caputo sense is defined as follows [36]:For the Caputo fractional derivative operator, , we obtainFor the Riemann-Liouvill fractional integral and Caputo fractional derivative of order , we have the following relations.

Lemma 3. *If , , and , , then*

*Remark 4. *According to the above definitions of the fractional calculus, (13) can be rewritten in the fractional order form:

#### 4. Analysis of the Proposed Methods

In this section, we present the analysis of the proposed methods with their suitable algorithms for the fractional order problems.

##### 4.1. Picard Method (PM)

To present this method, let us consider the general fractional order problem with an arbitrary order [26–29]:where is the time fractional differential operator of order . According to the fractional integral operators, the fractional order problem (21a) and (21b) takes the equivalent fractional integral form: where , , and is the inverse of . The required solution for (22) which is also the solution for (21a) and (21b) can be obtained as the limit of a sequence of functions generated by the recurrence relation:where

##### 4.2. Adomian Decomposition Method (ADM)

To illustrate the idea of this method, let us consider the fractional order problem [30–34]:subject to the initial values:where are linear and nonlinear operators and is a nonhomogeneous term. The method is based on applying the fractional integral operator , the inverse of the fractional differential operator , to both sides of (24a) and (24b) to obtain

The ADM suggests that the solution be decomposed into the infinite series of components:and the nonlinear term in (24a) is decomposed aswhere are called Adomian polynomials. Substituting the decomposition series (26) and (27) into both sides of (25) gives

Following the decomposition method, we introduce the recurrence relation as

The Adomian polynomial can be calculated for all forms of nonlinearity according to specific algorithms constructed by Adomian. The general form of the Adomian polynomials formula for is

This formula is easy to compute. Finally, we approximate the solution by the truncated series:

#### 5. Applications

In this section, we illustrate the application of the two proposed methods to solve the nonlinear fractional order ordinary differential equation (20) subject to the boundary conditions (14a) and (14b).

##### 5.1. PM

Using (20) and (14a) and (14b), the initial value fractional order problemaccording to (22) and (23), becomesTherefore, by Wolframe Mathematica 10 Package, we can obtain the following first few components of the solution:and so on. In the same manner, the rest of the components can be obtained. The* 4th-order term* solution for (32), in series form, is given by

In the special case, , (35) givesUsing the boundary conditions in (14a) and (14b) with the initial conditions in (32), the unknowns and for fixed values of and in (36) can be easily determined. In case of no-slip boundary, then and For , the solution isand in case of slip boundary, then and For , the solution is

##### 5.2. ADM

According to the recurrence relation (29), the initial value fractional order problem (32) giveswhereand, therefore, the first few components of the solution are as follows:and so on. In the same manner the rest of the components can be obtained. The* 4-term* solution is

In the special case, , (42) givesSimilarly, using the boundary conditions in (14a) and (14b) with the initial conditions in (32), the solution in case of no-slip boundary, for , isand in case of slip boundary, for , it is It is clear that the number of terms of the solution obtained by ADM in (42), (43), (44), and (45) is less than the number obtained by PM in (35), (36), (37), and (38).

The residual error of the problem is where is the* 4-term* approximate solution in (35) or (42) for (32).

It is important to note that, when , will be the exact solution. But, in nonlinear problems, this case does not usually occur.

It is clear from the obtained results that the above considered methods are used simply and accurately without linearization or discretization with their difficulties. Therefore, these methods are powerful methods for solving the nonlinear fractional order differential equations.

#### 6. Numerical Results and Discussion

In this work, an unsteady axisymmetric flow of incompressible, nonconducting Newtonian fluid squeezed between two circular plates passing through porous medium channel with slip and no-slip boundary conditions is considered. The obtained nonlinear fractional order problems are solved analytically through PM and ADM using Wolframe Mathematica 10 Package.

In addition to the fractional order , there are three parameters: constant containing permeability , Reynolds number , and slip parameter in the considered problem. Our discussions of the obtained results are based on different values of and these parameters. First, in case of no-slip boundary, the* 4th-order* approximate solutions obtained by the two methods for different values of , and are illustrated in Tables 1 and 2. Secondly, Tables 3 and 4 represent the* 4th-order* absolute residual errors for different values of , and . Thirdly, Tables 5, 6, 7, and 8 are in case of slip boundary at . Fourthly, Tables 9 and 10 and 11 and 12 represent the* 3rd-order* and* 2nd-order* absolute residual errors for different values of , and in case of no-slip and slip boundaries with for the two methods. Fifthly, the absolute difference between the ADM and PM solutions is illustrated in Tables 13 and 14 for various values of , and at in case of no-slip and slip boundaries conditions. Finally, the analysis of the absolute residual errors is shown in Tables 15 and 16 for various values of ,while keeping the other parameters fixed for different order solutions obtained by the two methods in case of no-slip and slip boundaries.