scholarly journals Numerical solutions of convective transport on Brinkman-viscoelastic fluid over a bluff body saturated in porous region

2021 ◽  
Vol 28 ◽  
pp. 101341
Author(s):  
S.F.H. Mohd Kanafiah ◽  
A.R.M. Kasim ◽  
S. Mohd Zokri ◽  
S. Shafie
Keyword(s):  
Viscoelastic Fluid ◽  
Bluff Body ◽  
Numerical Solutions ◽  
Convective Transport ◽  
Porous Region

scholarly journals Viscoelastic Fluid over a Stretching Sheet with Electromagnetic Effects and Nonuniform Heat Source/Sink

2010 ◽  
Vol 2010 ◽  
pp. 1-14 ◽  
Author(s):  
Kai-Long Hsiao
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Viscoelastic Fluid ◽  
Stretching Sheet ◽  
Numerical Solutions ◽  
Transfer Effects ◽  
Gauss Elimination ◽  
Heat Transfer Effects ◽  
Source Sink ◽  
Gauss Elimination Method

A magnetic hydrodynamic (MHD) of an incompressible viscoelastic fluid over a stretching sheet with electric and magnetic dissipation and nonuniform heat source/sink has been studied. The buoyant effect and the electric numberE1couple with magnetic parameterMto represent the dominance of the electric and magnetic effects, and adding the specific item of nonuniform heat source/sink is presented in governing equations which are the main contribution of this study. The similarity transformation, the finite-difference method, Newton method, and Gauss elimination method have been used to analyze the present problem. The numerical solutions of the flow velocity distributions, temperature profiles, and the important wall unknown values off''(0)andθ'(0)have been carried out. The parameter Pr,E1, orEccan increase the heat transfer effects, but the parameterMorA*may decrease the heat transfer effects.

Overstability of a Viscoelastic Fluid Layer Oscillating in a Vertical Periodic Motion and Heated From Below

1979 ◽  
Vol 46 (2) ◽  
pp. 454-456
Author(s):  
S. O. Onyegegbu
Keyword(s):  
Natural Frequency ◽  
Viscoelastic Fluid ◽  
Periodic Motion ◽  
Oscillation Frequency ◽  
Numerical Solutions ◽  
Fluid Layer ◽  
The Stability ◽  
Oscillation Frequencies

This Note examines the effect of vertical periodic motion on the stability characteristics of a viscoelastic fluid layer in a classical Benard geometry. Numerical solutions show that a resonant type behavior which enhances stability occurs at oscillation frequencies near the convective natural frequency of the viscoelastic fluid, while the effect of the periodic motion vanishes as the oscillation frequency gets very large.

Wavelet-based adaptive simulations of three-dimensional flow past a square cylinder

2014 ◽  
Vol 748 ◽  
pp. 433-456 ◽  
Author(s):  
Giuliano De Stefano ◽  
Oleg V. Vasilyev
Keyword(s):  
Reynolds Number ◽  
Bluff Body ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Adaptive Methods ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Eddy Simulation ◽  
Experimental Findings ◽  
Bluff Body Flows

AbstractThe wavelet-based eddy capturing approach is extended to three-dimensional bluff body flows, where the flow geometry is enforced through Brinkman volume penalization. The wavelet-collocation/volume-penalization combined method is applied to the simulation of vortex shedding flow behind an isolated stationary prism with square cross-section. Wavelet-based direct numerical simulation is conducted at low supercritical Reynolds number, where the wake develops fundamental three-dimensional flow structures, while wavelet-based adaptive large-eddy simulation supplied with the one-equation localized dynamic kinetic-energy-based model is performed at moderately high Reynolds number. The present results are in general agreement with experimental findings and numerical solutions provided by classical non-adaptive methods. This study demonstrates that the proposed hybrid methodology for modelling bluff body flows is feasible, accurate and efficient.

scholarly journals Similarity Analysis for Effects of Variable Diffusivity and Heat Generation/Absorption on Heat and Mass Transfer for a MHD Stagnation-Point Flow of a Convective Viscoelastic Fluid over a Stretching Sheet with a Slip Velocity

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
H. M. El-Hawary ◽  
Mostafa A. A. Mahmoud ◽  
Reda G. Abdel-Rahman ◽  
Abeer S. Elfeshawey
Keyword(s):  
Mass Transfer ◽  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Heat And Mass Transfer ◽  
Stagnation Point ◽  
Viscoelastic Fluid ◽  
Slip Velocity ◽  
Stretching Sheet ◽  
Numerical Solutions ◽  
Local Skin

A mathematical analysis has been carried out for stagnation-point heat and mass transfer of a viscoelastic fluid over a stretching sheet with surface slip velocity, concentration dependent diffusivity, thermal convective boundary conditions, and heat source/sink. The governing partial differential equations are reduced to a system of nonlinear ordinary differential equations using Lie group analysis. Numerical solutions of the resulting ordinary differential equations are obtained using shooting method. The influences of various parameters on velocity, temperature, and mass profiles have been studied. Also, the effects of various parameters on the local skin-friction coefficient, the local Nusselt number, and the local Sherwood number are given in graphics form and discussed.

Simulation of the Nonreacting Flow in a Bluff-Body Burner; Effect of the Diameter Ratio

1993 ◽  
Vol 115 (3) ◽  
pp. 474-484 ◽  
Author(s):  
Luis-Filipe Martins ◽  
Ahmed F. Ghoniem
Keyword(s):  
Composite Structures ◽  
Bluff Body ◽  
Convective Transport ◽  
Diameter Ratio ◽  
Wake Flow ◽  
Finite Area ◽  
Axisymmetric Vortex ◽  
Large Vortex ◽  
High Reynolds ◽  
Ring Elements

Axisymmetric vortex simulation is used to study the unsteady dynamics of the flowfield generated by the interaction between two concentric jets initially separated by a thick bluff-body. The computational scheme treats convective transport in a Lagrangian sense by discretizing the vorticity into a number of finite-area vortex ring elements which move along particle trajectories during each convective substep, thus reducing the numerical diffusion and allowing simulations at high Reynolds number. In this paper, investigation is focused on the time-dependent dynamics and the effect of the diameter ratio across the bluff-body on the wake flow. In both cases simulated, the dynamics is governed by the shedding of large vortex eddies from the inner and outer sides of the bluff-body. Mixing between the two streams is enhanced by the merging of these eddies downstream the bluff-body and the formation of composite structures. We find that the frequency of shedding, the level of fluctuations and the degree of organization are strongly dependent on the diameter ratio. The fluctuation associated with this shedding increases as the diameter ratio becomes larger. The origin and mechanism of shedding in each case are determined from the results.

scholarly journals Robust Mode Analysis

Mathematics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1057
Author(s):  
Gemunu H. Gunaratne ◽  
Sukesh Roy
Keyword(s):  
Experimental Data ◽  
Bluff Body ◽  
Numerical Solutions ◽  
Dynamic Mode Decomposition ◽  
Mode Analysis ◽  
Jet Flows ◽  
Dynamic Mode ◽  
Reacting Flow ◽  
Model Free ◽  
Wide Range

In this paper, we introduce a model-free algorithm, robust mode analysis (RMA), to extract primary constituents in a fluid or reacting flow directly from high-frequency, high-resolution experimental data. It is expected to be particularly useful in studying strongly driven flows, where nonlinearities can induce chaotic and irregular dynamics. The lack of precise governing equations and the absence of symmetries or other simplifying constraints in realistic configurations preclude the derivation of analytical solutions for these systems; the presence of flow structures over a wide range of scales handicaps finding their numerical solutions. Thus, the need for direct analysis of experimental data is reinforced. RMA is predicated on the assumption that primary flow constituents are common in multiple, nominally identical realizations of an experiment. Their search relies on the identification of common dynamic modes in the experiments, the commonality established via proximity of the eigenvalues and eigenfunctions. Robust flow constituents are then constructed by combining common dynamic modes that flow at the same rate. We illustrate RMA using reacting flows behind a symmetric bluff body. Two robust constituents, whose signatures resemble symmetric and von Karman vortex shedding, are identified. It is shown how RMA can be implemented via extended dynamic mode decomposition in flow configurations interrogated with a small number of time-series. This approach may prove useful in analyzing changes in flow patterns in engines and propulsion systems equipped with sturdy arrays of pressure transducers or thermocouples. Finally, an analysis of high Reynolds number jet flows suggests that tests of statistical characterizations in turbulent flows may best be done using non-robust components of the flow.

scholarly journals Combined Convective Transport of Brinkman-viscoelastic Fluid Across Horizontal Circular Cylinder with Convective Boundary Condition

2021 ◽  
Vol 89 (2) ◽  
pp. 15-24
Author(s):  
Siti Farah Haryatie Mohd Kanafiah ◽  
Abdul Rahman Mohd Kasim ◽  
Syazwani Mohd Zokri ◽  
Mohd Rijal Ilias
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Circular Cylinder ◽  
Viscoelastic Fluid ◽  
Transfer Process ◽  
Convective Boundary Condition ◽  
Heat Transfer Process ◽  
Convective Transport ◽  
Convective Boundary ◽  
Horizontal Circular Cylinder

Traditional heat transfer fluids frequently encounter several limitations in the heat transfer process, due to the lower thermal conductivity in heat transfer process industries, and also has an impact on the performance of heat transfer in industrial sectors. In order to overcome the problem, researchers have currently considered an alternative development of heat transfer of fluids. Hence, this study will concentrate on the problem of steady combined convective transport. In particular, the flow of Brinkman-viscoelastic fluid over a horizontal circular cylinder with the influence of convective boundary condition (CBC) was investigated. Using the necessary similarity transformation, the governing equations were converted into a less complicated form and numerically solved by using Runge-Kutta-Fehlberg-method, which was programmed in Maple software. The influence of Biot number, combined convection, Brinkman and viscoelastic parameters are analyzed and demonstrated in graphs and tables. Numerical result showed that the fluid velocity increased with improving conjugate and combined convection parameter, but decreased with increasing Brinkman and viscoelastic parameter. It is also discovered the reverse trend on temperature profiles.

Unsteady Hartmann flow with heat transfer of a viscoelastic fluid considering the Hall effect

2004 ◽  
Vol 82 (2) ◽  
pp. 127-139 ◽  
Author(s):  
H A Attia
Keyword(s):  
Heat Transfer ◽  
Hall Effect ◽  
Viscoelastic Fluid ◽  
Numerical Solutions ◽  
Constant Pressure ◽  
Electrically Conducting ◽  
Finite Difference Approximations ◽  
Energy Equations ◽  
External Uniform Magnetic Field ◽  
Newtonian Behavior

The unsteady Hartmann flow, with heat transfer, of an electrically conducting incompressible non-Newtonian viscoelastic fluid between two parallel horizontal nonconducting porous plates is studied taking into consideration the Hall effect. A sudden uniform and constant-pressure gradient, an external uniform magnetic field that is perpendicular to the plates, and uniform suction and injection through the surface of the plates are applied. The two plates are kept at different but constant temperatures while the Joule and viscous dissipations are taken into consideration. Numerical solutions for the governing momentum and energy equations are obtained using finite-difference approximations. The effect of the Hall term, the parameter describing the non-Newtonian behavior, and the velocity of suction and injection on both the velocity and temperature distributions is examined.PACS No.: 47.27.-i

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