Report no. 497, computation of the two-dimensional flow in a laminar boundary layer

1934 ◽  
Vol 218 (5) ◽  
pp. 639
1952 ◽  
Vol 19 (2) ◽  
pp. 185-194
Author(s):  
J. Kaye ◽  
T. Y. Toong ◽  
R. H. Shoulberg

Abstract The first part of a program to obtain reliable data on the rate of heat transfer to air moving at supersonic speeds in a tube has been devoted to measurements made on adiabatic supersonic flow of air in a tube. The details of these measurements have been described in a previous paper. The calculated quantities such as the local apparent friction coefficient, recovery factor, Mach number, and so forth, were obtained from the simple one-dimensional flow model for which the properties of the stream are uniform at any section, and boundary-layer effects are ignored. The analysis of some of the same data given in the previous paper is undertaken here with the aid of a simplified two-dimensional flow model. The supersonic flow in the tube is divided into a supersonic core of variable mass with the fluid remaining in the core undergoing a reversible adiabatic change of state, and a laminar boundary layer of variable mass. The compressible laminar boundary layer increases in thickness in the direction of flow, and then undergoes a transition to a turbulent boundary layer. The two-dimensional flow model is limited here to the region where a laminar boundary layer appears to be present in the entrance region of the tube. The results of the analysis based on the two-dimensional flow model indicate that where the flow in the tube boundary layer appears to be laminar, the measured pressures and temperatures in the tube for adiabatic supersonic flow of air could have been predicted, with sufficient accuracy for engineering problems, from measured data for supersonic flow of air over a flat plate with a laminar boundary layer, and with zero pressure gradient.


1955 ◽  
Vol 22 (3) ◽  
pp. 297-304
Author(s):  
Joseph Kaye ◽  
G. A. Brown

Abstract Reliable experimental data on local heat-transfer coefficients for supersonic flow of air in a round tube are reanalyzed in detail with the aid of an approximate two-dimensional flow model. The results are compared with similar results based on a one-dimensional flow model and with the theoretical predictions for supersonic flow over a flat plate and for flow in the entrance region of a tube when a laminar boundary layer is present. The two-dimensional flow model yields a better understanding of the phenomena which occur for diabatic supersonic flow of air in a round tube than that obtained with the aid of the one-dimensional flow model. The two-dimensional flow model shows that the core Mach number is nearly constant along the length of test section for a range of values of the inlet diameter Reynolds number. For a laminar boundary layer the values of the local Stanton number agree within a few per cent with the theoretical values for plate flow at the largest values of the inlet diameter Reynolds number.


1947 ◽  
Vol 14 (3) ◽  
pp. A213-A216
Author(s):  
R. C. Binder

Abstract A method is presented for calculating the efficiency of a diffuser for two-dimensional, steady, incompressible flow without separation. The method involves a combination of organized boundary-layer data and frictionless potential-flow relations. The potential velocity and pressure are found after the boundary-layer growth is determined by a trial-and-check calculation.


Author(s):  
D. W. Beard ◽  
K. Walters

AbstractThe Prandtl boundary-layer theory is extended for an idealized elastico-viscous liquid. The boundary-layer equations are solved numerically for the case of two-dimensional flow near a stagnation point. It is shown that the main effect of elasticity is to increase the velocity in the boundary layer and also to increase the stress on the solid boundary.


This paper focuses on unsteady, two-dimensional, flow boundary layer of a incompressible viscous electrically conducting and absorbing heat fluid along a semi-infinite vertical moving permeable plate in the presence of Chemical reaction and radiation effects. The dimensionless equations are analytically solved using perturbation procedure. The effects of the different flow fluid parameters on velocity, temperature and concentration fields with in the boundary layer have been examined with the help of graphs.


1972 ◽  
Vol 23 (1) ◽  
pp. 1-6 ◽  
Author(s):  
B R Bostock ◽  
W A Mair

SummaryMeasurements in two-dimensional flow on rectangular cylinders confirm earlier work of Nakaguchi et al in showing a maximum drag coefficient when the height h of the section (normal to the stream) is about 1.5 times the width d. Reattachment on the sides of the cylinder occurs only for h/d < 0.35.For cylinders of D-shaped section (Fig 1) the pressure distribution on the curved surface and the drag are considerably affected by the state of the boundary layer at separation, as for a circular cylinder. The lift is positive when the separation is turbulent and negative when it is laminar. It is found that simple empirical expressions for base pressure or drag, based on known values for the constituent half-bodies, are in general not satisfactory.


1936 ◽  
Vol 40 (310) ◽  
pp. 681-708
Author(s):  
V. V. Golubev

The theory of the aerofoil has now been studied to such an extent that, from this province, it is hardly possible to expect further material improvement in its aerodynamical qualities : profiles differing but little from an inverse of a parabola (Joukovski profile) would appear to be the theoretical ideal. Subsequent important progress in that respect may be sought only in another direction, viz., in the application of a series of supplementary contrivances having a marked influence on the properties of the flow around the aerofoil. Here we are referring to such devices as the sucking away of the boundary layer (Absaugeflügel), or the insertion of appliances on the aerofoil itself. Nevertheless, up to the present, only one of the very earliest attempts in this direction, namely, the slotted wing, has developed sufficiently to be in any way widely adopted in contemporary aircraft construction.


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