scholarly journals Boundary Layer Theory for a Particulate Suspension

1994 ◽  
Vol 116 (1) ◽  
pp. 147-153 ◽  
Author(s):  
A. J. Chamkha ◽  
J. Peddieson

Order of magnitude considerations are employed to develop boundary layer equations for two phase particle/fluid suspension flows. It is demonstrated that a variety of possibilities exist and three of these are examined in detail. Two are applied to the problem of flow past a semi-infinite flat plate.

1974 ◽  
Vol 62 (1) ◽  
pp. 145-161 ◽  
Author(s):  
D. R. Kassoy

A study is made of uniform flow past a semi-infinite flat plate with a similarity injection distribution of boundary-layer magnitude. Attention is focused on a solution at exactly the critical injection rate for which classical boundary-layer theory predicts the blow-off singularity. Following a description of the more recent interaction analyses which also fail at the critical rate, a new theory is developed which leads to physically meaningful results. In particular, it is shown that the non-monotonic variation in wall shear with increasing injection rate near the critical value, noted by Klemp & Acrivos (1972), is real. A delicate interplay of weak pressure interactions and viscous effects is shown to be responsible for this surprising phenomenon.


2010 ◽  
Vol 132 (10) ◽  
Author(s):  
Y. Liao

This work presents a unique and unified formulation to solve the laminar film condensation two-phase boundary layer equations for the free, mixed, and forced convection regimes in the absence or presence of noncondensables. This solution explores the vast space of mixed convection across the four cornerstones of laminar film condensation boundary layer theory, two established by Koh for pure vapor condensation in the free or forced convection regimes and the other two established by Sparrow corresponding to condensation with noncondensables. This formulation solves the space of mixed convection completely with Koh and Sparrow’s solutions shown to be merely four specific cases of the current solution.


2012 ◽  
Vol 15 (6) ◽  
pp. 585-593
Author(s):  
M. Jana ◽  
S. Das ◽  
S. L. Maji ◽  
Rabindra N. Jana ◽  
S. K. Ghosh

This paper contains a study of the similarity solutions of the boundary layer equations for the case of strong blowing through a porous surface. The main part of the boundary layer is thick and almost inviscid in these conditions, but there is a thin viscous region where the boundary layer merges into the main stream. The asymptotic solutions appropriate to these two regions are matched to one another when the blowing velocity is large. The skin friction is found from the inner solution, which is independent of the outer solution, but the displacement thickness involves both solutions and is of more complicated form.


1987 ◽  
Vol 109 (4) ◽  
pp. 997-1002 ◽  
Author(s):  
A. Nakayama ◽  
H. Koyama ◽  
F. Kuwahara

The two-phase boundary layer theory was adopted to investigate subcooled free-convection film boiling over a body of arbitrary shape embedded in a porous medium. A general similarity variable which accounts for the geometric effect on the boundary layer length scale was introduced to treat the problem once for all possible two-dimensional and axisymmetric bodies. By virtue of this generalized transformation, the set of governing equations and boundary conditions for an arbitrary shape reduces into the one for a vertical flat plate already solved by Cheng and Verma. Thus, the numerical values furnished for a flat plate may readily be tranlsated for any particular body configuration of concern. Furthermore, an explicit Nusselt number expression in terms of the parameters associated with the degrees of subcooling and superheating has been established upon considering physical limiting conditions.


2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Sadia Siddiqa ◽  
Naheed Begum ◽  
M. A. Hossain ◽  
Rama Subba Reddy Gorla

This article is concerned with the class of solutions of gas boundary layer containing uniform, spherical solid particles over the surface of rotating axisymmetric round-nosed body. By using the method of transformed coordinates, the boundary layer equations for two-phase flow are mapped into a regular and stationary computational domain and then solved numerically by using implicit finite difference method. In this study, a rotating hemisphere is used as a particular example to elucidate the heat transfer mechanism near the surface of round-nosed bodies. We will investigate whether the presence of dust particles in carrier fluid disturbs the flow characteristics associated with rotating hemisphere or not. A comprehensive parametric analysis is presented to show the influence of the particle loading, the buoyancy ratio parameter, and the surface of rotating hemisphere on the numerical findings. In the absence of dust particles, the results are graphically compared with existing data in the open literature, and an excellent agreement has been found. It is noted that the concentration of dust particles’ parameter, Dρ, strongly influences the heat transport rate near the leading edge.


1970 ◽  
Vol 42 (3) ◽  
pp. 561-584 ◽  
Author(s):  
S. N. Brown ◽  
K. Stewartson

A study is made of the laminar flow in the neighbourhood of the trailing edge of an aerofoil at incidence. The aerofoil is replaced by a flat plate on the assumption that leading-edge stall has not taken place. It is shown that the critical order of magnitude of the angle of incidence α* for the occurrence of separation on one side of the plate is$\alpha^{*} = O(R^{\frac{1}{16}})$, whereRis a representative Reynolds number, for incompressible flow, and α* =O(R−¼) for supersonic flow. The structure of the flow is determined by the incompressible boundary-layer equations but with unconventional boundary conditions. The complete solution of these fundamental equations requires a numerical investigation of considerable complexity which has not been undertaken. The only solutions available are asymptotic solutions valid at distances from the trailing edge that are large in terms of the scaled variable of orderR−⅜, and a linearized solution for the boundary layer over the plate which gives the antisymmetric properties of the aerofoil at incidence. The value of α* for which separation occurs is the trailing-edge stall angle and an estimate is obtained from the asymptotic solutions. The linearized solution yields an estimate for the viscous correction to the circulation determined by the Kutta condition.


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