Waves in Random and Complex Media ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/twrm20 Thermal aspects of radiation in Casson fluid with nonlinear stretching surface: non-similar solutions Muavia Mansoor, M. Shoaib Kamran, Qazi Mahmood Ul-Hassan & Muhammad Irfan To cite this article: Muavia Mansoor, M. Shoaib Kamran, Qazi Mahmood Ul-Hassan & Muhammad Irfan (2022): Thermal aspects of radiation in Casson fluid with nonlinear stretching surface: nonsimilar solutions, Waves in Random and Complex Media, DOI: 10.1080/17455030.2022.2071502 To link to this article: https://doi.org/10.1080/17455030.2022.2071502 Published online: 12 May 2022. Submit your article to this journal View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=twrm20 WAVES IN RANDOM AND COMPLEX MEDIA https://doi.org/10.1080/17455030.2022.2071502 Thermal aspects of radiation in Casson fluid with nonlinear stretching surface: non-similar solutions Muavia Mansoora , M. Shoaib Kamrana , Qazi Mahmood Ul-Hassana and Muhammad Irfanb a Department of Mathematics, University of Wah, Wah, Pakistan; b Department of Mathematical Sciences, Federal Urdu University of Arts Science and Technology, Islamabad, Pakistan ABSTRACT ARTICLE HISTORY A mathematical model is established to peruse the effects of viscous dissipation and thermal radiation on non-Newtonian, incompressible, steady, mixed convective flow next to a nonlinear vertical stretching surface. The Rosseland approximation is used in the energy equation to describe the radiative heat flux. Non-similarity transformation has been used to convert coupled partial differential equations (PDEs) into dimensionless PDEs. For dealing with nonsimilar problems, the non-similarity method is more effective as compared to similarity transformation. First, this method utilizes transformations to reduce governing equations into dimensionless systems of PDEs, and further, it utilizes different truncation levels to get a detailed set of PDEs. MATLAB built-in solver bvp4c is used to solve obtained dimensionless PDEs. Parameters describing the nature of flow like local Sherwood number, local Nusselt number and local skin friction coefficient are explored in detail after finding the numerical solution. The effects of Casson number, Radiation number, Eckert number, Schmidt number, Prandtl number and Grashof number for heat and mass transfer on concentration, temperature and velocity profiles are specified with the aid of graphs. Received 27 December 2021 Accepted 22 April 2022 Nomenclature α β βT βC D σ∗ k∗ Ec k1 ν l thermal diffusivity Casson parameter coefficients of thermal expansion coefficients of concentration expansion mass diffusivity Stefan-Boltzman absorption coefficient Eckert number chemical reaction rate kinematic viscosity reference length CONTACT Muavia Mansoor muavia.mansoor@uow.edu.pk © 2022 Informa UK Limited, trading as Taylor & Francis Group KEYWORDS Casson fluid; thermal radiation; viscous dissipation; mixed convection; Matlab solver bvp4c 2 M. MANSOOR ET AL. Nux Shx T∞ Sc U0 σ Pr Cf Cp GrC qr Grl Re k Rd Tw γ local Nusselt number local Sherwood number fluid temperature at free stream Schmidt number reference velocity electrical conductivity Prandtl number skin coefficient friction specific heat Olutal Grashof number radiative heat flux thermal Grashof number Reynolds number thermal conductivity radiation parameter ratio of velocities fluid temperature surface rate of Chemical reaction parameter Introduction Non-Newtonian fluids have numerous applications in our daily life such as in textile, polymer industries, food making, paper industries and agriculture sector to find out below groundwater storage. Examples of these fluids are blood, honey, oils, and greases. As we know that there is a nonlinear relation between stress and strain for non-Newtonian fluid that’s why it is impossible to describe all characteristics of non-Newtonian fluid in a single equation. As a result, many non-Newtonian fluid models [1–5] have been developed depending on different physical parameters. The most famous among these fluids is the Casson fluid. Casson fluid was founded in 1959 for the very first time while studying the flow of oil suspension printing ink type [6]. By applying small stress, Casson fluid performs like an elastic solid. And by applying a large amount of stress, Casson fluid flows. So, this fluid behaves like solid as well as liquid. As we know that human blood contains different elements like protein and red blood cells in plasma, so it is also an example of Casson fluid. Casson fluid model presents flow properties of blood when the shear rate is low. Other examples are jelly, honey, and sauce. Many researchers have been interested in studying Casson fluid due to its numerous applications in the food sector and biological treatments. Oka was the first one who examined the flow of Casson fluid through a tube [7]. T. Hayat et al. [8] considered boundary layer flow of Casson fluid with mass transfer by using similarity transformation. Mustafa et al. also discussed Casson fluid with heat transfer in moving plates and applied the Homotopy analysis method to find out analytical solutions and observed effects of physical parameters [9]. Mukhopadhyay investigated the effects of blowing for Casson fluid and calculated numerical solution [10]. Pramanik studied the effects of heat flux and thermal radiation on Casson fluid [11]. Seini et al. investigated the effect of a chemical reaction and magnetic effect for Casson fluid [12] and used the Newton Raphson method to solve transformed ordinary differential equations and presented results with WAVES IN RANDOM AND COMPLEX MEDIA 3 help of graphs. Recently T Anwar et al. [13] analyzed Casson fluid over an infinite plate with effects of thermal conductivity and heat mass transfer and used suitable dimensionless variables and solutions were calculated with the help of Laplace transform. The main purpose of this research was to observe ramped temperature and velocity conditions on Casson fluid. When fluid is heated, it rises, leaves a low-pressure region behind and cool fluid rushes in. In this way, cool fluid is heated. This motion is due to temperature difference which results in density difference and this process is called convection. Free convection is due to density variation while forced convection is due to some external agent like a blower for gas. The relative contribution of forced and free convection in the total rate of convective heat transfer is determined by the ratio of Grashof number and square of Reynolds number. If this ratio is less, then forced convection dominates, and if this ratio is greater, then free convection dominates. If this ratio is in between, then relative contribution of both convections must be considered for the calculation of total convective heat transfer. T. Hayat et al. examined mixed convection flow of Casson nanofluid with chemical reaction, magnetic effect and in the presence of thermal radiation [14]. Izadi et al. also presented mixed convection flow with heat transfer of carbon nanotubes [15]. M. Mushtaq et al. [16] explored the mixed convection flow of second-grade viscoelastic fluid and calculated numerical solutions. M. J. H. Munshi et al. [17] examined mixed convection of nanofluid in a porous medium with heat effects. Thermal conductivity is a physical property that depends upon temperature. Thermal conductivity is defined as the rate of heat transfer through a unit length of material per unit temperature difference. According to Batchelor and Animasaun, thermal conductivity varies with variation in temperature [18,19] Large amount of work has been done that explains the effect of thermal conductivity on flowing fluids. Chaim et al. observed thermal conductivity in boundary layer flow of 2D Newtonian fluid in a porous medium [20]. Attia [21] presented unsteady flow between two parallel plates with variable thermal conductivity and viscosity. Jawad et al. used the Attia model for observing both thermal conductivity and viscosity of flow in vertical channels. He observed that heat transfer and fluid flow decrease with an increase in thermal conductivity [22]. Gbadeyan et al. [23] investigated the effects of thermal conductivity on viscous, incompressible Casson nanofluid. After solving the system of equations, the effects of different physical parameters like Sherwood number and Nusselt number were observed and plotted graphically. T. Hayat et al. [24] investigated mixed convection flow over a stretching surface with variable thermal conductivity and observed the effects of governing parameters. T. Hayat also discussed Casson fluid over a stretching sheet with the effect of thermal conductivity and presented a series of solution [25]. Mondal and Pal [26] investigated the effects of thermal conductivity and temperaturedependent viscosity in MHD strained fluid flow. More detail about current studies can be reported in references [27–31]. In fluid flow, viscous dissipation is a resistive force, and it leads to a permanent change of shear stresses into heat energy in contiguous layers and is acknowledged as a dissipation function. Brinkman was the first one who observed heat generation by viscous dissipation [32]. Wu and Cheng examined viscous dissipation effects for horizontal plate channels in which the lower plate is heated, and the upper plate is cooled [33]. Orhan et al. [34] discussed the viscous dissipation effect for Poiseuille flow and fully developed flow is studied. Oliveria and Pinho [35] observed forced convection flow in channel flows with the addition 4 M. MANSOOR ET AL. of the viscous dissipation effect. It was observed that due to viscous dissipation, fluid elasticity increases. Ajayi et al. [36] focused on the viscous dissipation effect for Casson fluid over the melting surface, a term indicating viscous dissipation is included in the energy equation. Similarity transformation was applied to convert partial differential equations into systems of ordinary differential equations. Noor et al. [37] presented Casson nanofluid model with effects of viscous dissipation and chemical reaction and Buongiorno’s model was considered to observe these effects. It was examined that viscous dissipation increases fluid temperature and heat transfer. After obtaining a solution comparison was made with existing results. Dada et al. [38] examined Williamson fluid under effects of viscous dissipation, chemical reaction and radiation in a porous medium with the addition of variable thermal conductivity and viscosity. Solutions were obtained by using suitable transformation and then by using the Homotopy analysis method to find out analytical solutions. After obtaining solutions, the effects of involved parameters are analyzed. Yang et al. [39] also studied Casson fluid model with the viscous dissipation effect and analyzed the viscoelastic effect in porous medium and calculated a numerical solution. For more information, see references [40–42]. Here the concept of MHD radiative flow of Casson fluid under the aspect of convective heat transport has been reported. The properties of Joule heating and viscous dissipation are also examined for the heat transport phenomenon. The current article has the following novelties. Firstly the local non-similar solutions have been achieved. Secondly, the deliberated problem has an essential use in cooling progression for the determination of refining mechanical possessions of the heated sheet that cannot be refrigerated by the usage of old-fashioned approaches established on the base fluids. Third, the aspect of radiation is very significant in industrial activities for the project of trustworthy apparatus, nuclear control plants, vapor turbines and numerous thrust strategies for planes, artillery, satellites and interplanetary automobiles. Lastly, the magnetic effects have vital uses in physics and industries. Numerous metallurgical developments comprise the chilling of uninterrupted floorings or threads by sketching them via a quiescent liquid, and in the procedure of illustration, these floorings are occasionally stretched. In these circumstances, the possessions of the closing creation are contingent to a great amount on the percentage of chilling by sketching such strips in an electrically conducting liquid focus to a magnetic field and the specific desired in the closing creation. Thus, under these novelties, we examined Casson fluid with properties of radiation, MHD, Joule heating, viscous dissipation and convective effects. The graphs are plotted and discussed. Problem formulations Consider steady, laminar, and incompressible two-dimensional non-Newtonian Casson fluid flowing over stretched plates under the effects of mixed convection, viscous dissipation, and thermal radiation. The x - axis is taken in the direction of flow and y - axis is perpendicular to the direction of flow. u and v are components of velocity in x and y direcx tions. The stretching velocity is Uw (x) = u0 e /l in a positive x direction. Tw and T∞ are temperatures of fluids at the wall and free stream. Similarly, Cw and C∞ are representing concentration at the wall and free stream (Figure 1). WAVES IN RANDOM AND COMPLEX MEDIA 5 Figure 1. Geometry of the problem. Equations representing Casson fluid [14] under effects of viscous dissipation, thermal radiation and mixed convection are stated as ux + vy = 0 (1) uux + vuy = ν 1 + 1 β (uTx + vTy ) = α(Tyy ) + uyy + gβT (T − T∞ ) + gβC (C − C∞ ) − ν Cp 1+ 1 β (uy )2 − σ B0 u ρ 2 1 σ B0 2 2 (qr )y + u ρCp ρCp (uCx + vCy ) = D(Cyy ) (2) (3) (4) The equivalent boundary conditions will be hf u = Uw (x), v = 0, ∂T ∂y = − kf (Tw − T), C = Cw aty = 0 T → T∞ , u → 0, C → C∞ at y → ∞ (5) Using Rosseland approximation, the expression for the radiative heat flux qr is given by qr = − 4σ ∗ 4 T 3k∗ y (6) It is assumed that for radiative heat flux, temperature deviation within the flow is very small, the term T 4 can also be expounded as a linear function of temperature T with the assistance of Taylor’s series expansion about T∞ and by ignoring all the higher terms, given as 3 4 T4 ∼ T − 3T∞ = 4T∞ By using (6) and (7) into (3), it is obtained 1 16σ ∗ T∞ 3 ν σ B0 2 u2 2 (uTx + vTy ) = α + (T 1 + ) + ) + (u yy y 3k∗ ρCp Cp β ρCp (7) (8) 6 M. MANSOOR ET AL. Transformation of the governing system of equations Consider [43] the non-similar transformations, in which we have two independent variables η is called pseudo similar while ξ is non-similar, from mathematics perspective it is just a trick or method to reduce the dimensionality of the problem, or it is often used to reduce a PDEs to PDEs. 2x Uw T − T∞ C − C∞ ξ = e l ,η = y andϕ(ξ , η) = , ψ(x, y) = 2υlUw f (ξ , η), θ(ξ , η) = 2υl Tw − T∞ Cw − C∞ ∂f υUw ∂f ∂f u = Uw (ξ , η), v = − f (ξ , η) + 4ξ (ξ , η) + η (ξ , η) (9) ∂η 2l ∂ξ ∂η By applying non-similarity transformations in Equations (2), (4) and (8) diminishes to (10)–(12) 2 ∂f ∂η 2 + 4ξ ∂ 2 f ∂f ∂f ∂ 2 f ∂f ∂ 2f 1 ∂ 3f + M + 2θ Grl + 2Grc ϕ − f 2 − 4ξ = 1 + ∂ξ ∂η ∂η ∂η ∂ξ ∂η2 ∂η β ∂η3 (10) Pr −f Sc −f ∂θ ∂θ ∂f ∂f ∂θ 1 + 4ξ − 4ξ − 1+ ∂η ∂ξ ∂η ∂ξ ∂η β ∂ϕ ∂ϕ ∂f ∂f ∂ϕ + 4ξ − 4ξ ∂η ∂ξ ∂η ∂ξ ∂η Ec (f ) − J 2 ∂f ∂η 2 = θ 1 + 4Rd 3 (11) = ∂ 2ϕ ∂η2 (12) Subject to the boundary conditions ∂f f (ξ , η) = 1, f (ξ , η) = −4ξ ∂ξ , ϕ(ξ , η) = 1, θ (ξ , η) = −Bi(1 − θ)atη = 0 θ(ξ , η) → 0, f (ξ , η) → 0, ϕ(ξ , η) → 0atη → ∞ 4σ ∗ T∞ 3 k1 l k kk∗ , α = ρCp , γ = Ue , 2σ B0 2 l 2σ B0 2 lU0 ρU0 , J = ρCp (Tw −T∞) . where Pr = υα , Rd = gβC (Cw −C∞ )l3 ,M υ2 = Ec = Uw 2 Cp (Tw −T∞ ) , Grl = gβT (Tw −T∞ )l3 , υ2 (13) GrC = Local similarity method By using the local similarity method (which remains necessary for using non-similarity transformation), Equations (10)–(12) are assumed to be sufficiently small so that they can be approximated by zero, so consider ξ ∂(.) ∂ξ = 0 f = θ = 1 1+ Pr 1+ (2f − ff − 2Grl θ − 2Grc ϕ + Mf ) 2 1 β 4Rd 3 ϕ = Sc(−f ϕ ) (14) 1 2 2 −f θ − 1 + Ec (f ) − J(f ) β (15) (16) WAVES IN RANDOM AND COMPLEX MEDIA 7 subject to the boundary conditions f (ξ , η) = 1, f (ξ , η) = 0, θ (ξ , η) = −Bi(1 − θ), ϕ(ξ , η) = 1atη = 0 (17) θ(ξ , η) → 0, f (ξ , η) → 0, ϕ(ξ , η) → 0atη → ∞ Local non-similarity method Moving toward the local non-similarity results of Equations (10)–(12), where prime derivatives are with respect to η while p, q and g are the derivatives of f , θ and ϕ with respect to ξ . Hence, by supposing ∂f ∂θ ∂ϕ ∂ 2f ∂f ∂ 2θ ∂θ ∂ 2ϕ ∂ϕ = p, = = p , = q, = = q , = g, = = g ∂ξ ∂ξ ∂η ∂ξ ∂ξ ∂ξ ∂η ∂ξ ∂ξ ∂ξ ∂η ∂ξ 1 2 (2f + 4ξ p f − ff − 4ξ pf − 2Grl θ − 2Grc ϕ + Mf ) f = (18) 1 1+ β Pr 1 2 2 θ = 4ξ qf − f θ − 4ξ pθ − 1 + (19) Ec (f ) − J(f ) β 1 + 4R3d ϕ = Sc(4ξ gf − f ϕ − 4ξ pϕ ) (20) Subject to the boundary conditions f (ξ , η) = 1, f (ξ , η) = −4ξ p, θ (ξ , η) = −Bi(1 − θ), ϕ(ξ , η) = 1atη = 0 θ(ξ , η) → 0, f (ξ , η) → 0, ϕ(ξ , η) → 0atη → ∞ (21) Taking derivative w.r.t ξ for (18)–(20), it is obtained p = 1 1+ 2 Pr q = (4f p + 4p f + 4ξ p − 5pf − fp − 4ξ pp − 2Grl q − 2Grc g + Mp ) (22) 1 β 1+ 4Rd 3 1 4ξ qp − 5pθ − fq − 4ξ pq + 4qf − 2 1 + β Ec f p − 2Jf p g = Sc(−5pϕ − fg + 4gf + 4ξ gp − 4ξ pg ) (23) (24) subject to the boundary conditions p (ξ , η) = 0, p(ξ , η) = 0, q (ξ , η) = Bi ∗ q, g(ξ , η) = 0atη = 0 q(ξ , η) → 0, p (ξ , η) → 0, g(ξ , η) → 0atη → ∞ The terms ∂g(ξ ,η) ∂p(ξ ,η) ∂ξ , ∂ξ and ∂q(ξ ,η) ∂ξ (25) and their derivatives with respect to η are ignored. Solution procedure Since the non-similarity method only gives the non-dimensional equations which are further needed to be solved using some analytical or numerical method. For this reason, a Matlab built-in utility bvp4c is used to solve the obtained differential equations from 8 M. MANSOOR ET AL. non-similarity methods. The Matlab solver bvp4c solves the scalar or system of differential equations using the three-stage Lobatto IIIa formula. Since the obtained equations contain two independent variables, to solve these equations, one independent variable was held to be fixed, and so remaining equations become ordinary differential equations. For solving equations, using a Matlab solver, it requires a function for differential equations and a function for getting boundary conditions. For giving the information of differential equations to the MATLAB solver, the conversion of the system of second or higher-order differential equations into a system of first order ordinary differential equations is required. For this reason, conversion into a system of first-order differential equations can be expressed as f = f2 , f = f3 f = 1 1+ 1 β θ = f5 θ = Pr 1+ (2f2 2 + 4ξ f9f2 − f1 f3 − 4ξ f8 f3 − 2Grl f4 − 2Grc f6 + Mf2 ) 1 4ξ f11 f2 − f1 f5 − 4ξ f8 f5 − 1 + Ec (f3 )2 − Jf2 2 β 4Rd 3 ϕ = f7 ϕ = Sc(4ξ f13 f2 − f1 f7 − 4ξ f8 f7 ) p = f9 , p = f10 p = 1 1+ 1 β q = f12 q = Pr 1+ 4Rd 3 (4f2 f8 + 4f9 f2 + 4ξ f9 2 − 5f8 f3 − f1 f10 − 4ξ f8 f10 − 2Grl f11 − 2Grc f13 + Mf9 ) 1 4ξ f11 f9 − 5f8 f5 − f1 f12 − 4ξ f8 f12 + 4f11 f2 − 2 1 + Ec f3 f8 − 2Jf2 f8 β g = f14 g = Sc(−5f8 f7 − f1 f14 + 4f13 f2 + 4ξ f13 f9 − 4ξ f8 f14 ) where f = f1 , θ = f4 , ϕ = f6 , p = f8 , q = f11 and g = f13 [f0,2 − 1, f0,1 + 2ξ f8 , f1,2 , f0,5 + Bi ∗ (1 − f4 ), f1,4 , f0,6 − 1, f1,6 , f0,9 , f0,8 , f1,9 , f0,12 − Bi ∗ f11 , f1,11 , f0,13 , f1,13 ]t where f1 and f0 depicts boundary conditions on right and left end points of the domain, respectively Result and discussion This part mainly explains about velocity profile behavior, temperature and concentration and sketches have been drawn for these profiles against different parameters. Figures 2–5 endorse the reverberation of distinct parameters for velocity profile. Figures 6–9 evaluate WAVES IN RANDOM AND COMPLEX MEDIA 9 Figure 2. Velocity profile with variation of M. Figure 3. Velocity profile with variation of β. changing trends in the temperature profile. Figure 10 elucidates changing development in concentration sketches. Figure 2 describes the effect of magnetic parameter M on the velocity profile. By increasing values for magnetic parameters, velocity profile de-escalates. Figure 3 explains the velocity distribution for the Casson parameter β. By increasing values of β, the velocity profile depletes. Figures 4 and 5 are plotted to observe the effects of 10 M. MANSOOR ET AL. Figure 4. Velocity profile with variation of Grashof number for mass transfer Grc . Figure 5. Velocity profile with variation of Grashof number for heat transfer Grl . Grashof numbers Grl and Grc on the velocity of the fluid. By enhancing the values of both Grashof numbers for heat and mass transfer results in an accelerating velocity profile. As WAVES IN RANDOM AND COMPLEX MEDIA 11 Figure 6. Temperature profile with variation of J. Figure 7. Observation for Temperature profile with changing values of Eckert number Ec. Grashof number is the ratio of buoyancy force to restraining (viscous) force, and its increasing values is responsible for lowering the viscosity which in turn enhances the velocity of 12 M. MANSOOR ET AL. Figure 8. Temperature profile with variation of Prandtl number Pr. Figure 9. Temperature profile with variation of Radiation number Rd. the fluid. Figure 6 demonstrates the effects of the Joule heating parameter J for temperature profile. By enhancing values for the Joule heating parameter, the temperature profile shows increasing behavior. WAVES IN RANDOM AND COMPLEX MEDIA 13 Figure 10. Concentration profile with variation of Schmidt number Sc. Figure 7 clarifies about effects of Eckert number Ec on temperature profile, and it can be seen that temperature profile increases with increasing values of the Eckert numberEc. Figure 8 explicates the results of Prandtl number Pr on temperature profile and it shows that temperature profile is decreasing function of Prandtl number Pr. As Pr is the ratio of momentum to thermal diffusivity and is used to calculate the heat transfer between fluid and surface of the sheet. With the increase of Pr results in lowering the thermal conductivity, consequently, conduction even thermal boundary layer thickness decreases. That’s, the outcome is a decrease in the temperature profile. Figure 9 shows the curves for radiation parameter Rd against temperature profile and it is observed that by increasing values for radiation parameter, temperature profile shows decreasing behavior. Figure 10 expounds on the concentration profile and the effects of the Schmidt number Sc on the mass transfer profile. Decreasing pattern is observed in this figure with increasing values of Schmidt number Sc. Table 1 explains values for local Sherwood numbers, local Nusselt and skin friction coefficient, with respect to changings in different parameters. This table represents an increase in skin friction coefficient by enhancing the value of parameters Grc and Ec while it depicts decreasing behavior by enhancing values of Sc, β, PrandRd. Local Nusselt number shows decreasing behavior by increment in Prandtl number because there is an inverse relation between Prandtl number and thermal diffusivity so by increasing Prandtl number thermal diffusivity decreases and as a result temperature profile also decreases. Local Nusselt number also shows decreasing behavior by increasing value of Grashof number for mass transfer. By enhancing values of Sc, βandRd and decreasing values of PrandEc, the local Nusselt number shows an increasing behavior. Local Sherwood number shows increasing 14 M. MANSOOR ET AL. Table 1. Numerical values of Skin friction coefficient, local Nusselt number and local Sherwood number with Variation of parameters using Grl = 2.1, J = 0.3, M = 0.2, Bi = 0.3. Grc Sc β Pr Ec 1+ Rd 2.2 2.3 1 β f (0) 1.8556 2.0044 2.5478 2.2428 2.0034 1.9854 1.9421 1.9412 1.9497 2.1473 2.1371 2.1286 0.4 0.5 1.1 1.2 1 1.5 0.2 0.3 0.2 0.3 − 1+ 4Rd 3 −φ (0) θ (0) 0.0843 0.0830 0.0758 0.0801 0.0931 0.0932 0.0934 0.0840 0.0748 0.0383 0.0491 0.0602 0.6104 0.6117 0.5002 0.5587 0.5805 0.5811 0.5824 0.5778 0.5752 0.5822 0.5831 0.5839 Table 2. Comparison of numerical values for heat flux with Grl = Grc = Ec = J = M = Bi = 0. θ(0) Pr 1 2 3 5 10 Ishak [44] 0.9542 1.4715 1.8619 2.5001 3.6604 Present Error S. Pramanik [11] Present Error 0.9532 1.4711 1.8694 2.5231 3.6602 1 × 10−3 4 × 10−4 75 × 10−4 23 × 10−3 2 × 10−4 0.9547 1.4714 1.8691 2.5001 3.6603 0.9532 1.4711 1.8694 2.5231 3.6602 15 × 10−4 3 × 10−4 3 × 10−4 23 × 10−3 1 × 10−4 behavior by increasing values of Grc , Sc, β, Ec andRd. Local Sherwood number de-escalates by increasing values for Prandtl number Pr. Table 2 illustrates the comparison between the past and present research for evaluating numerical values of the heat flux with varying Prandtl number Pr. From this Table 2, it can be seen that the present results are in good agreement with those computed in the past research. Conclusion In this work, we observed the effects of various physical parameters on mixed convective Casson fluid under the effects of viscous dissipation and thermal radiations. We explored the Casson fluid model represented by a system of PDEs, and non-similarity transformation is used to convert given equations into dimensionless PDEs. Transformed PDEs are reflected as ODEs and explained by Matlab solver Bvp4c. The central observations are stated as (1) Velocity profile proliferated by means of decreasing the Casson parameter. (2) Velocity profile proliferated by increasing Grashof numbers of heat and mass transfer. (3) Velocity profile depleted by increasing values of the magnetic parameter. (4) Temperature profile depleted by means of enhancing values of Prandtl number. (5) Temperature profile shows increasing behavior with enhancing values of radiation parameter and joule heating parameter. (6) Concentration profile depleted by increasing values of Schmidt number. WAVES IN RANDOM AND COMPLEX MEDIA 15 Disclosure statement No potential conflict of interest was reported by the author(s). References [1] Djukic DS. Hiemenz magnetic flow of power-law fluids. Eur J Mech B Fluids. 2002;21(3):317–324. [2] Dorier C, Tichy J. Behavior of a Bingham-like viscous fluid in lubrication flows. J Non-Newtonian Fluid Mech. 1992;45:291–310. [3] Wilkinson W. The drainage of a Maxwell liquid down a vertical plate. Chem Eng J. 1970;1:255–257. [4] Xiao-Feng Z, Lei G. Effect of multipolar interaction on the effective thermal conductivity of nanofluids. Chin Phys. 2007;16:2028–2032. 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