scholarly journals The influence of variation of electroconductivity on ionized gas flow in the boundary layer along a porous wall

2006 ◽  
Vol 33 (2) ◽  
pp. 149-179 ◽  
Author(s):  
Slobodan Savic ◽  
Branko Obrovic
Keyword(s):  
Boundary Layer ◽  
Gas Flow ◽  
Longitudinal Velocity ◽  
Porous Wall ◽  
Outer Edge ◽  
Ionized Gas ◽  
Boundary Layer Equations ◽  
Characteristic Boundary ◽  
Longitudinal Variable ◽  
Similarity Method

This paper investigates ionized gas flow in the boundary layer when its electroconductivity is varied. The flow is planar and the contour is porous. At first, it is assumed that the ionized gas electroconductivity ? depends only on the longitudinal variable. Then we adopt that it is a function of the ratio of the longitudinal velocity and the velocity at the outer edge of the boundary layer. For both electroconductivity variation laws, by application of the general similarity method, the governing boundary layer equations are brought to a generalized form and numerically solved in a four-parametric three times localized approximation. Based on many tabular solutions, we have shown diagrams of the most important nondimensional values and characteristic boundary layer functions for both of the assumed laws. Finally, some conclusions about influence of certain physical values on ionized gas flow in the boundary layer have been drawn. .

scholarly journals Investigation of the ionized gas flow adjacent to porous wall in the case when electroconductivity is a function of the longitudinal velocity gradient

2010 ◽  
Vol 14 (1) ◽  
pp. 89-102
Author(s):  
Slobodan Savic ◽  
Branko Obrovic ◽  
Dusan Gordic ◽  
Sasa Jovanovic
Keyword(s):  
Boundary Layer ◽  
Electric Fields ◽  
Velocity Gradient ◽  
Gas Flow ◽  
Numerical Solutions ◽  
Longitudinal Velocity ◽  
Porous Wall ◽  
The Body ◽  
Ionized Gas ◽  
Boundary Layer Equations

This paper studies the laminar boundary layer on a body of an arbitrary shape when the ionized gas flow is planar and steady and the wall of the body within the fluid porous. The outer magnetic field is perpendicular to the fluid flow. The inner magnetic and outer electric fields are neglected. The ionized gas electroconductivity is assumed to be a function of the longitudinal velocity gradient. Using transformations, the governing boundary layer equations are brought to a general mathematical model. Based on the obtained numerical solutions in the tabular forms, the behavior of important non-dimensional quantities and characteristics of the boundary layer is graphically presented. General conclusions about the influence of certain parameters on distribution of the physical quantities in the boundary layer are drawn.

scholarly journals Ionized gas boundary layer on a porous wall of the body within the electroconductive fluid

2004 ◽  
Vol 31 (1) ◽  
pp. 47-71 ◽  
Author(s):  
Branko Obrovic ◽  
Slobodan Savic
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Gas Flow ◽  
Numerical Solutions ◽  
Porous Wall ◽  
The Body ◽  
Generalized Equations ◽  
Ionized Gas ◽  
Boundary Layer Equations ◽  
Longitudinal Coordinate

This paper investigates the ionized gas flow in the boundary layer, when the contour of the body within the fluid is porous. Ionized gas is exposed to the influence of the outer magnetic field induction Bm = Bm(x), which is perpendicular to the contour of the body within the fluid. It is presumed that the electroconductivity of the ionized gas is a function only of the longitudinal coordinate, i.e. ? = ?(x). By means of adequate transformations, the governing boundary layer equations are brought to a generalized form. The obtained generalized equations are solved in a four-parameter localized approximation. Based on the obtained numerical solutions, diagrams of important physical values and characteristics of the boundary layer have been made. Conclusions have also been drawn.

scholarly journals The influence of the magnetic field on the ionized gas flow adjacent to the porous wall

2010 ◽  
Vol 14 (suppl.) ◽  
pp. 183-196
Author(s):  
Slobodan Savic ◽  
Branko Obrovic ◽  
Milan Despotovic ◽  
Dusan Gordic
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Gas Flow ◽  
Great Influence ◽  
Porous Wall ◽  
Boundary Layer Separation ◽  
The Body ◽  
Ionized Gas ◽  
Friction Function ◽  
The Magnetic Field

This paper studies the influence of the magnetic field on the planar laminar steady flow of the ionized gas in the boundary layer. The present outer magnetic field is homogenous and perpendicular to the body within the fluid. The gas of the same physical characteristics as the gas in the main flow is injected (ejected) through the contour of the body. The governing boundary layer equations for different forms of the electroconductivity variation law are transformed, brought to a generalized form and solved numerically in a four-parametric approximation. It has been determined that the magnetic field, through the magnetic parameter, has a great influence on certain quantities and characteristics of the boundary layer. It has also been shown that this parameter has an especially significant influence on the non-dimensional friction function, and hence the boundary layer separation point.

scholarly journals Analysis of the axisymmetrical ionized gas boundary layer adjacent to porous contour of the body of revolution

2016 ◽  
Vol 20 (2) ◽  
pp. 529-540
Author(s):  
Slobodan Savic ◽  
Branko Obrovic ◽  
Nebojsa Hristov
Keyword(s):  
Boundary Layer ◽  
Gas Flow ◽  
Mhd Flow ◽  
The Body ◽  
Generalized Solutions ◽  
Body Of Revolution ◽  
Ionized Gas ◽  
Bodies Of Revolution ◽  
Boundary Layer Equations ◽  
Longitudinal Coordinate

The ionized gas flow in the boundary layer on bodies of revolution with porous contour is studied in this paper. The gas electroconductivity is assumed to be a function of the longitudinal coordinate x. The problem is solved using Saljnikov's version of the general similarity method. This paper is an extension of Saljnikov?s generalized solutions and their application to a particular case of magnetohydrodynamic (MHD) flow. Generalized boundary layer equations have been numerically solved in a four-parametric localized approximation and characteristics of some physical quantities in the boundary layer has been studied.

Influence of Favourable Pressure Gradient on the Heat Transfer in Boundary Layer

2010 ◽  
Author(s):  
Alexey Yu. Sakhnov ◽  
Eduard P. Volchkov ◽  
Maxem S. Makarov
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Pressure Gradient ◽  
Cross Flow ◽  
Porous Wall ◽  
Skin Friction Coefficient ◽  
Outer Edge ◽  
Boundary Layer Equations ◽  
Accelerated Flow ◽  
Asymptotic Suction

In the present paper, we analyze, both numerically and analytically, the influence a favourable pressure gradient has on the characteristics of dynamic boundary layer. It is shown that at a certain value of the pressure gradient asymptotic conditions can be reached in laminar boundary layer, with the skin-friction coefficient value being independent of the Reynolds number, like in the case of asymptotic suction of boundary layer through the porous wall. Some analogy between the two types of flow can be traced: in both cases, namely, at porous suction and in the boundary layer of an accelerated flow, a cross flow is generated, directed from the outer edge of the boundary layer toward the wall. For the conditions of the two types, an approximate analytical solution to the boundary-layer equations has been obtained. It is shown that in problems with first- and second-kind boundary conditions the favourable pressure gradient exerts an influence on the heat-transfer characteristics.

scholarly journals Boundary layer of the dissociated gas flow over a porous wall under the conditions of equilibrium dissociation

2005 ◽  
Vol 32 (2) ◽  
pp. 165-190 ◽  
Author(s):  
Branko Obrovic ◽  
Dragisa Nikodijevic ◽  
Slobodan Savic
Keyword(s):  
Boundary Layer ◽  
Gas Flow ◽  
Air Flow ◽  
Porous Wall ◽  
The Body ◽  
Boundary Layer Equations ◽  
Equilibrium Dissociation ◽  
Dissociated Air

This paper studies the ideally dissociated air flow in the boundary layer when the contour of the body within the fluid is porous. By means of adequate transformations, the governing boundary layer equations of the problem are brought to a general form. The obtained equations are numerically solved in a three-parametric localized approximation. Based on the obtained solutions, very important conclusions about behavior of certain boundary layer physical values and characteristics have been drawn.

Supersonic laminar boundary layer near the plane of symmetry of a cone at incidence

1972 ◽  
Vol 51 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Bernard Roux
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Laminar Boundary Layer ◽  
External Flow ◽  
Leeward Side ◽  
Detailed Consideration ◽  
Boundary Layer Equations ◽  
Similarity Method ◽  
Supersonic Laminar ◽  
Critical Incidence

Supersonic laminar boundary-layer equations near the plane of symmetry of a cone at incidence are treated by the similarity method. Numerical integration of differential equations governing such a flow is performed, taking into consideration the temperature dependence of the Prandtl numberPrand viscosity μ throughout the boundary layer. On the leeward side, a detailed consideration of the solutions shows the existence of two solutions up to a critical incidence beyond which it appears that no solution may be found. Calculations carried out for a set of values of the external flow Mach number show up a significant effect of this parameter on the behaviour of the boundary layer.

scholarly journals On the ionized gas boundary layer adjacent to the bodies of revolution in the case of variable electroconductivity

2013 ◽  
Vol 17 (2) ◽  
pp. 555-566
Author(s):  
Branko Obrovic ◽  
Slobodan Savic ◽  
Vanja Sustersic
Keyword(s):  
Boundary Layer ◽  
The Body ◽  
Gas Flows ◽  
Generalized Equations ◽  
Ionized Gas ◽  
Bodies Of Revolution ◽  
Concrete Form ◽  
General Similarity ◽  
Transformation Of Variables ◽  
Similarity Method

This paper studies the ionized gas i.e. air flow in an axisymmetrical boundary layer adjacent to the bodies of revolution. The contour of the body within the fluid is nonporous. The ionized gas flows under the conditions of equilibrium ionization. A concrete form of the electroconductivity variation law has been assumed and studied here. Through transformation of variables and introduction of sets of parameters, V. N. Saljnikov's version of the general similarity method has been successfully applied. Generalized equations of axisymmetrical ionized gas boundary layer have been obtained and then numerically solved in a three-parametric localized approximation.

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