scholarly journals Three-dimensional magnetohydrodynamic nanofluid thin-film flow with heat and mass transfer over an inclined porous rotating disk

2019 ◽  
Vol 11 (8) ◽  
pp. 168781401986975 ◽  
Author(s):  
Muhammad Jawad ◽  
Zahir Shah ◽  
Aurangzeb Khan ◽  
Saeed Islam ◽  
Hakeem Ullah
Keyword(s):  
Thin Film ◽  
Boundary Layer ◽  
Differential Equations ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Liquid System ◽  
Thin Film Flow ◽  
Homotopy Analysis ◽  
Injection Effect ◽  
Film Flows

In the present study, the three-dimensional Darcy–Forchheimer magnetohydrodynamic thin-film nanofluid containing flow over an inclined steady rotating plane is observed. Nanofluid thin-film flows are taken thermally radiated and suction/injection effect is also considered. By similarity variables, the partial differential equations are transformed into a set of first-ordinary differential equations (ODES). By Homotopy Analysis Method, the required ODES is solved. The boundary layer over an inclined steady rotating plane is plotted and observed in detail for the velocity, [Formula: see text], and [Formula: see text] profiles. The influence of various embedded parameters such as variable thickness, [Formula: see text]Pr, and thermophoretic parameter on velocity, [Formula: see text], and [Formula: see text] profile. The influence of many parameters is explained by graphs for the velocity, [Formula: see text], and [Formula: see text]. The crucial terms of Nusselt number and Sherwood number have also been observed numerically and physically for [Formula: see text] and [Formula: see text]. Radiation phenomena is the cause of energy to the liquid system. For more rotation parameters, the thermal boundary-layer thickness is reduced.

scholarly journals Three-Dimensional Casson Nanofluid Thin Film Flow over an Inclined Rotating Disk with the Impact of Heat Generation/Consumption and Thermal Radiation

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 248 ◽  
Author(s):  
Anwar Saeed ◽  
Zahir Shah ◽  
Saeed Islam ◽  
Muhammad Jawad ◽  
Asad Ullah ◽  
...  
Keyword(s):  
Thin Film ◽  
Boundary Layer ◽  
Differential Equations ◽  
Thermal Boundary Layer ◽  
Energy Transport ◽  
Film Flow ◽  
Three Dimensional ◽  
Concentration Profiles ◽  
Thin Film Flow ◽  
The Impact

In this research, the three-dimensional nanofluid thin-film flow of Casson fluid over an inclined steady rotating plane is examined. A thermal radiated nanofluid thin film flow is considered with suction/injection effects. With the help of similarity variables, the partial differential equations (PDEs) are converted into a system of ordinary differential equations (ODEs). The obtained ODEs are solved by the homotopy analysis method (HAM) with the association of MATHEMATICA software. The boundary-layer over an inclined steady rotating plane is plotted and explored in detail for the velocity, temperature, and concentration profiles. Also, the surface rate of heat transfer and shear stress are described in detail. The impact of numerous embedded parameters, such as the Schmidt number, Brownian motion parameter, thermophoretic parameter, and Casson parameter (Sc, Nb, Nt, γ), etc., were examined on the velocity, temperature, and concentration profiles, respectively. The essential terms of the Nusselt number and Sherwood number were also examined numerically and physically for the temperature and concentration profiles. It was observed that the radiation source improves the energy transport to enhance the flow motion. The smaller values of the Prandtl number, Pr, augmented the thermal boundary-layer and decreased the flow field. The increasing values of the rotation parameter decreased the thermal boundary layer thickness. These outputs are examined physically and numerically and are also discussed.

scholarly journals Numerical and Analytical Investigation of an Unsteady Thin Film Nanofluid Flow over an Angular Surface

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 486 ◽  
Author(s):  
Haroon Rasheed ◽  
Zeeshan Khan ◽  
Ilyas Khan ◽  
Dennis Ching ◽  
Kottakkaran Nisar
Keyword(s):  
Thin Film ◽  
Boundary Layer ◽  
Brownian Motion ◽  
Prandtl Number ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Motion Parameter ◽  
Concentration Profiles ◽  
Thin Film Flow ◽  
Brownian Motion Parameter

In the present study, we examine three-dimensional thin film flow over an angular rotating disk plane in the presence of nanoparticles. The governing basic equations are transformed into ordinary differential equations by using similarity variables. The series solution has been obtained by the homotopy asymptotic method (HAM) for axial velocity, radial velocity, darning flow, induced flow, and temperature and concentration profiles. For the sake of accuracy, the results are also clarified numerically with the help of the BVPh2- midpoint method. The effect of embedded parameters such as the Brownian motion parameter Nb, Schmidt number Sc, thermophoretic parameter and Prandtl number Pr are explored on velocity, temperature and concentration profiles. It is observed that with the increase in the unsteadiness factor S, the thickness of the momentum boundary layer increases, while the Sherwood number Sc, with the association of heat flow from sheet to fluid, reduces with the rise in S and results in a cooling effect. It is also remarkable to note that the thermal boundary layer increases with the increase of the Brownian motion parameter Nb and Prandtl number Pr, hindering the cooling process resulting from heat transfer.

scholarly journals Impact of Nonlinear Thermal Radiation on MHD Nanofluid Thin Film Flow over a Horizontally Rotating Disk

2019 ◽  
Vol 9 (8) ◽  
pp. 1533 ◽  
Author(s):  
Zahir Shah ◽  
Abdullah Dawar ◽  
Poom Kumam ◽  
Waris Khan ◽  
Saeed Islam
Keyword(s):  
Thin Film ◽  
Thermal Radiation ◽  
Film Flow ◽  
Rotating Disk ◽  
Point Of View ◽  
Working Fluid ◽  
Nonlinear Thermal Radiation ◽  
Thin Film Flow ◽  
Homotopy Analysis ◽  
The Impact

Nanoscience can be stated as a superlative way of changing the properties of a working fluid. Heat transmission features during the flow of nanofluids are an imperative rule from the industrial and technological point of view. This article presents a thin film flow of viscous nanofluids over a horizontal rotating disk. The impact of non-linear thermal radiation and a uniform magnetic field is emphasized in this work. The governing equations were transformed and solved by the homotopy analysis method and the ND-Solve technique. Both analytical and numerical results are compared graphically and numerically, and excellent agreement was obtained. Skin friction and the Nusselt number were calculated numerically. It is concluded that the thin film thickness of nanofluids reduces with enhanced values of the magnetic parameter. In addition, the nanofluid temperature was augmented with increasing values of the thermal radiation parameter. The impact of emerging parameters on velocities and temperature profiles were obtainable through graphs and were deliberated on in detail.

EXPERIMENTAL INVESTIGATION OF FLOW RESPONSE TO STATIONARY DISTURBANCE IN ROTATING-DISK FLOW

2019 ◽  
Vol XVI (2) ◽  
pp. 13-22
Author(s):  
Muhammad Ehtisham Siddiqui
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Careful Analysis ◽  
Laboratory Frame ◽  
Transition To Turbulence ◽  
Turbulent Regime ◽  
Mean Velocity ◽  
Layer Flow

Three-dimensional boundary-layer flow is well known for its abrupt and sharp transition from laminar to turbulent regime. The presented study is a first attempt to achieve the target of delaying the natural transition to turbulence. The behaviour of two different shaped and sized stationary disturbances (in the laboratory frame) on the rotating-disk boundary layer flow is investigated. These disturbances are placed at dimensionless radial location (Rf = 340) which lies within the convectively unstable zone over a rotating-disk. Mean velocity profiles were measured using constant-temperature hot-wire anemometry. By careful analysis of experimental data, the instability of these disturbance wakes and its estimated orientation within the boundary-layer were investigated.

scholarly journals Triple Solutions of Carreau Thin Film Flow with Thermocapillarity and Injection on an Unsteady Stretching Sheet

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3177 ◽  
Author(s):  
Kohilavani Naganthran ◽  
Ishak Hashim ◽  
Roslinda Nazar
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Differential Equations ◽  
Film Thickness ◽  
Stretching Sheet ◽  
Film Flow ◽  
Problem Solver ◽  
Thin Film Flow ◽  
Unsteady Stretching Sheet ◽  
Negative Film

Thin films and coatings which have a high demand in a variety of industries—such as manufacturing, optics, and photonics—need regular improvement to sustain industrial productivity. Thus, the present work examined the problem of the Carreau thin film flow and heat transfer with the influence of thermocapillarity over an unsteady stretching sheet, numerically. The sheet is permeable, and there is an injection effect at the surface of the stretching sheet. The similarity transformation reduced the partial differential equations into a system of ordinary differential equations which is then solved numerically by the MATLAB boundary value problem solver bvp4c. The more substantial effect of injection was found to be the reduction of the film thickness at the free surface and development of a better rate of convective heat transfer. However, the increment in the thermocapillarity number thickens the film, reduces the drag force, and weakens the rate of heat transfer past the stretching sheet. The triple solutions are identified when the governing parameters vary, but two of the solutions gave negative film thickness. Detecting solutions with the most negative film thickness is essential because it implies the interruption in the laminar flow over the stretching sheet, which then affects the thin film growing process.

Instabilities of the von Kármán Boundary Layer

2015 ◽  
Vol 67 (3) ◽  
Author(s):  
R. J. Lingwood ◽  
P. Henrik Alfredsson
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Direct Numerical Simulations ◽  
Layer Model ◽  
Complex Flow ◽  
Von Karman ◽  
Dimensional Boundary ◽  
Flow Configurations ◽  
Von Kármán

Research on the von Kármán boundary layer extends back almost 100 years but remains a topic of active study, which continues to reveal new results; it is only now that fully nonlinear direct numerical simulations (DNS) have been conducted of the flow to compare with theoretical and experimental results. The von Kármán boundary layer, or rotating-disk boundary layer, provides, in some senses, a simple three-dimensional boundary-layer model with which to compare other more complex flow configurations but we will show that in fact the rotating-disk boundary layer itself exhibits a wealth of complex instability behaviors that are not yet fully understood.

Thin-Film Flow at Moderate Reynolds Number

2000 ◽  
Vol 122 (4) ◽  
pp. 774-778 ◽  
Author(s):  
Kenneth J. Ruschak ◽  
Steven J. Weinstein
Keyword(s):  
Thin Film ◽  
Boundary Layer ◽  
Free Surface ◽  
Film Flow ◽  
Previous Analysis ◽  
Vertical Wall ◽  
Integral Approach ◽  
Internal Boundary ◽  
Thin Film Flow ◽  
Moderate Reynolds Number

Viscous, laminar, gravitationally-driven flow of a thin film over a round-crested weir is analyzed for moderate Reynolds numbers. A previous analysis of this flow utilized a momentum integral approach with a semiparabolic velocity profile to obtain an equation for the film thickness (Ruschak, K. J., and Weinstein, S. J., 1999, “Viscous Thin-Film Flow Over a Round-Crested Weir,” ASME J. Fluids Eng., 121, pp. 673–677). In this work, a viscous boundary layer is introduced in the manner of Haugen (Haugen, R., 1968, “Laminar Flow Around a Vertical Wall,” ASME J. Appl. Mech. 35, pp. 631–633). As in the previous analysis of Ruschak and Weinstein, the approximate equations have a critical point that provides an internal boundary condition for a bounded solution. The complication of a boundary layer is found to have little effect on the thickness profile while introducing a weak singularity at its beginning. The thickness of the boundary layer grows rapidly, and there is little cumulative effect of the increased wall friction. Regardless of whether a boundary layer is incorporated, the approximate free-surface profiles are close to profiles from finite-element solutions of the Navier-Stokes equation. Similar results are obtained for the related problem of developing flow on a vertical wall (Cerro, R. L., and Whitaker, S., 1971, “Entrance Region Flows With a Free Surface: the Falling Liquid Film,” Chem. Eng. Sci., 26, pp. 785–798). Less accurate results are obtained for decelerating flow on a horizontal wall (Watson, E. J., 1964, “The Radial Spread of a Liquid Jet Over a Horizontal Plane,” J. Fluid Mech. 20, pp. 481–499) where the flow is not gravitationally driven. [S0098-2202(00)01904-0]

On the stability of three-dimensional boundary layers with application to the flow due to a rotating disk

1955 ◽  
Vol 248 (943) ◽  
pp. 155-199 ◽  
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Wave Velocity ◽  
Critical Points ◽  
Three Dimensional ◽  
Rotating Disk ◽  
Velocity Profiles ◽  
Wave Number ◽  
Two Dimensional ◽  
China Clay

A phenomenon of boundary-layer instability is discussed from the theoretical and experimental points of view. The china-clay evaporation technique shows streaks on the surface, denoting a vortex system generated in the region of flow upstream of transition. Experiments on a swept wing are described briefly, while experiments on the flow due to a rotating disk receive much greater attention. In the latter case, the axes of the disturbance vortices take the form of equi-angular spirals, bounded by radii of instability and of transition. A frequency analysis of the disturbances shows that there is a narrow band of disturbance components of high amplitude, some frequencies within this band corresponding to disturbances fixed relative to the surface and others corresponding to moving waves. Furthermore, the determination of velocity profiles for the rotating-disk flow is described, the agreement with the theoretical solution for laminar flow being quite satisfactory; for turbulent flow, however, the empirical theories are not very satisfactory. In order to explain the vortex phenomenon just discussed, the general equations of motion in orthogonal curvilinear co-ordinates are examined by superimposing an infinitesimal disturbance periodic in space and time on the main flow, and linearizing for small disturbances. An important result is that, within the range of certain approximations, the velocity component in the direction of propagation of the disturbance may be regarded as a two-dimensional flow for stability purposes; then the problem of stability formally resembles the well-known two dimensional problem. However, it is important to emphasize that this result—namely, that the flow curvature has little influence on stability—is applicable only to the possible modes of instability in a local region. The nature of three-dimensional flows is discussed, and the importance of co-ordinates along and normal to the stream-lines outside the boundary layer is examined. In accord with the formal two-dimensional nature of the instability, there is a whole class of velocity distributions, corresponding to different directions, which may exhibit instability. The question of stability at infinite Reynolds number is examined in detail for these profiles. As for ordinary two-dimensional flows, the wave velocity of the disturbance must lie somewhere between the maximum and minimum of the velocity profile considered. The points where the wave velocity equals the fluid velocity are called critical points, of which most of the profiles considered have two. Then Tollmien’s criterion that velocity profiles with a point of inflexion are unstable at infinite Reynolds number is extended to the case of profiles with two critical points. One particular profile—namely, that for which the point of inflexion lies at the point of zero velocity—may generate neutral disturbances of zero phase velocity, corresponding to the disturbances visualized by the china-clay technique. A variational method for the solution of certain of the eigenvalue problems associated with stability at infinite Reynolds number is derived, found by comparison with an exact solution to be very accurate, and applied to the rotating disk. The fixed vortices predicted by the theory have as their axes equi-angular spirals of angle 103°, in good agreement with experiment, but the agreement between theoretical and experimental wave number is not good, the discrepancy being attributed to viscosity. Finally, the correlation between the experimentally observed and theoretically possible disturbances is discussed and certain conclusions drawn therefrom. The streamlines of the disturbed boundary layer show the existence of a double row of vortices, one row of which produces the streaks in the china clay. Application of the theory to other physical phenomena is described.

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