scholarly journals Study of two-dimensional boundary layer thin film fluid flow with variable thermo-physical properties in three dimensions space

AIP Advances ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 105318 ◽  
Author(s):  
Zaman Palwasha ◽  
Noor Saeed Khan ◽  
Zahir Shah ◽  
Saeed Islam ◽  
Ebenezer Bonyah
Keyword(s):  
Thin Film ◽  
Boundary Layer ◽  
Fluid Flow ◽  
Physical Properties ◽  
Three Dimensions ◽  
Two Dimensional ◽  
Dimensional Boundary ◽  
Layer Thin Film ◽  
Thermo Physical Properties

scholarly journals Study of two dimensional boundary layer flow of a thin film second grade fluid with variable thermo-physical properties in three dimensions space

Filomat ◽  
2019 ◽  
Vol 33 (16) ◽  
pp. 5387-5405 ◽  
Author(s):  
Noor Khan
Keyword(s):  
Thin Film ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Second Grade ◽  
Two Dimensional ◽  
Second Grade Fluid ◽  
Similarity Transformations ◽  
Dimensional Boundary ◽  
Grade Fluid ◽  
Layer Flow

The formation of three dimensional study from two dimensional study due to high intensified magnetic field is investigated for a thin film second-grade fluid with variable fluid properties. The effects of Soret, Dufour, thermophoresis, thermal radiation and viscous dissipation are taken into account in the problem. Similarity transformations are employed to convert the governing equations into dimensionless form which have been solved by using homotopy analysis method (HAM). Quite real results are achieved with the help of emerging parameters which are shown through different graphs for velocities, temperature and concentration profiles.

On Numerical Prediction of the Stability of Hypersonic Boundary-Layer Flow Over a Row of Microcavities

2003 ◽  
Author(s):  
Vassilios Theofilis ◽  
Michel O. Deville ◽  
Peter W. Duck ◽  
Alexander Fedorov
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Flow Instability ◽  
Viscous Sublayer ◽  
Hypersonic Boundary Layer ◽  
Two Dimensional ◽  
Flow Stabilization ◽  
Two Dimensional Flow ◽  
Dimensional Boundary ◽  
Layer Flow

This paper is concerned with the structure of steady two–dimensional flow inside the viscous sublayer in hypersonic boundary–layer flow over a flat surface in which microscopic cavities (‘microcavities’) are embedded. Such a so–called Ultra Absorptive Coating (UAC) has been predicted theoretically [1] and demonstrated experimentally [2] to stabilize passively hypersonic boundary–layer flow. In an effort to further quantify the physical mechanism leading to flow stabilization, this paper focuses on the nature of the basic flows developing in the configuration in question. Direct numerical simulations are performed, addressing firstly steady flow inside a singe microcavity, driven by a constant shear, and secondly a model of a UAC surface in which the two–dimensional boundary layer over a flat plate and a minimum nontrivial of two microcavities embedded in the wall are solved in a coupled manner. The influence of flow– and geometric parameters on the obtained solutions is illustrated. Based on the results obtained, the limitations of currently used theoretical methodologies for the description of flow instability are identified and suggestions for the improved prediction of the instability characteristics of UAC surfaces are discussed.

Numerical Study of Turbulent Convective in Upward Flows of Supercritical Water in the Triangular Lattice Fuel Rod Bundle

2014 ◽  
Author(s):  
Mohsen Modirshanechi ◽  
Kamel Hooman ◽  
Iman Ashtiani Abdi ◽  
Pourya Forooghi
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Nusselt Number ◽  
Turbulent Boundary Layer ◽  
Physical Properties ◽  
Supercritical Water ◽  
Triangular Lattice ◽  
Rod Bundles ◽  
Fuel Rod ◽  
Thermo Physical Properties

Convection heat transfer in upward flows of supercritical water in triangular tight fuel rod bundles is numerically investigated by using the commercial CFD code, ANSYS Fluent© 14.5. The fuel rod with an inner diameter of 7.6 mm and the pitch-to-diameter ratio (P/D) of 1.14 is studied for mass flux ranging between 550 and 1050 kg/m2s and heat flux of 560 kW/m2 at pressures of 25 MPa. V2F eddy viscosity turbulence model is used and, to isolate the effect of buoyancy, constant values are used for thermo-physical properties with Boussinesq approximation for the density variation with temperature in the momentum equations. The computed Nusselt number normalized by that of the same Reynolds number with no buoyancy against the buoyancy parameter proposed by Jackson and Hall’s criterion. Mentioned results are compared with V2F turbulence model whereas strong nonmonotonic variation of the thermo-physical properties as function of temperature have been applied to the commercial CFD code using user defined function (UDF) technique. A significant decrease in Nusselt number was observed in the range of 10-6<Grq/Reb3.425Prb0.8<5×10-6 before entering a serious heat transfer deterioration regime. Based on an analysis of the shear-stress distribution in the turbulent boundary layer and the significant variation of the specific heat across the turbulent boundary layer, it is found that the same mechanism that leads to impairment of turbulence production in concentric annular pipes is present in triangular lattice fuel rod bundles at supercritical pressure.

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