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.

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.

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.

A Note on the Resistance of Bodies of Revolution and Ship Forms

1974 ◽  
Vol 18 (03) ◽  
pp. 153-168
Author(s):  
N. Matheson ◽  
P. N. Joubert
Keyword(s):  
Boundary Layer ◽  
Reasonable Agreement ◽  
The Body ◽  
Experimental Results ◽  
Body Of Revolution ◽  
Bodies Of Revolution ◽  
Boundary Layer Development ◽  
Layer Development

A simple so-called 'equivalent' body of revolution is proposed for reflex ship forms in an attempt to simplify calculation of the boundary layer over a ship's hull when there is no wavemaking. How­ever, exhaustive testing of one body of revolution did not produce a favorable comparison with re­sults for the corresponding reflex model. Gadd's recently proposed theory was used to calculate the boundary-layer development over the body of revolution. Reasonable agreement was obtained between the calculated and experimental results.

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.

Analysis of Laminar Boundary-Layer Separation in Retarded Flow over Bodies of Revolution

2021 ◽  
Author(s):  
Ahmer Mehmood ◽  
Babar Hussain Shah ◽  
Muhammad Usman ◽  
Iqrar Raza
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Flow Separation ◽  
Boundary Layer Separation ◽  
The Body ◽  
Bodies Of Revolution ◽  
Layer Separation ◽  
Transverse Curvature ◽  
Favorable Pressure Gradient ◽  
Curvature Parameter

Laminar boundary-layer separation phenomenon is one of the interesting and important aspects of boundary-layer flows. It occurs in various physical situations because of decreasing wall shear stress. Retarded flow velocities are one of the reasons to happen this event. Flow separation can be prevented or delayed by utilizing bodies of revolution as surface transverse curvature produces the effects of the nature of favorable pressure-gradient which in turn increases wall shear stress that keeps the flow attached to the surface. Bodies of revolution whose body contour follows power-law form also play a vital role to delay flow separation. Bodies of revolution of varying cross-sections and involving surface transverse curvature (TVC) are utilized to examine their effects on flow separation. Particularly, a convex transverse curvature has been considered due to its effects of the nature of favorable pressure-gradient which causes to delay the flow separation. A retarded flow velocity of Görtler’s type is considered in this study to investigate flow separation process. A detailed analysis is provided to understand the flow separation by calculating separation points under various assumptions. It has been observed that the body contours exponent n and the convex transverse curvature parameter k play an assistive role in the delaying of boundary-layer separation even under the influence of strong retardation. Results are presented through various Tables and graphs in order to highlight the role of the power-law exponent of external velocity m, the convex transverse curvature parameter k, and the body contours exponent n on separation points.

Turbulent Boundary Layers on Bodies of Revolution

1982 ◽  
Vol 26 (02) ◽  
pp. 135-147 ◽  
Author(s):  
A.J. Smits ◽  
P. N. Joubert
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layers ◽  
The Body ◽  
Two Dimensional ◽  
Body Of Revolution ◽  
Calculation Methods ◽  
Bodies Of Revolution ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow ◽  
Simple Summation

Turbulent boundary-layer flow over two arbitrary bodies of revolution was investigated by comparison with the flow over a two-dimensional wing-like body. For each body of revolution this wing" was first shaped to copy the body of revolution pressure distribution and then modified to have the same longitudinal curvature. The results were interpreted in terms of the effects of the extra rates of strain associated with longitudinal curvature and lateral divergence. These effects could be distinguished reasonably clearly and the experimental results should prove useful for testing calculation methods. Comparison with the calculations of Bradshaw et al [8, 9] shows that there occurs a strong interaction between the extra rates of strain due to convex curvature and divergence and that the implied simple summation of these two effects cannot be justified.

Calculation of Subsonic Normal Force and Centre of Pressure Position of Bodies of Revolution Using a Slender Body Theory – Boundary Layer Method

1980 ◽  
Vol 31 (1) ◽  
pp. 1-25
Author(s):  
K.D. Thomson
Keyword(s):  
Boundary Layer ◽  
Velocity Distribution ◽  
Normal Force ◽  
The Body ◽  
Slender Body ◽  
Centre Of Pressure ◽  
Slender Body Theory ◽  
Bodies Of Revolution ◽  
Slender Bodies ◽  
Body Theory

SummaryThe aim of this paper is to present a method for predicting the aerodynamic characteristics of slender bodies of revolution at small incidence, under flow conditions such that the boundary layer is turbulent. Firstly a panel method based on slender body theory is developed and used to calculate the surface velocity distribution on the body at zero incidence. Secondly this velocity distribution is used in conjunction with an existing boundary layer estimation method to calculate the growth of boundary layer displacement thickness which is added to the body to produce the effective aerodynamic profile. Finally, recourse is again made to slender body theory to calculate the normal force curve slope and centre of pressure position of the effective aerodynamic profile. Comparisons made between predictions and experiment for a number of slender bodies extending from highly boattailed configurations to ogive-cylinders, and covering a large range of boundary layer growth rates, indicate that the method is useful for missile design purposes.

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 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. .

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