THEORETICAL INVESTIGATIONS OF A SUPERSONIC LAMINAR BOUNDARY LAYER WITH FOREIGN-GAS INJECTION

AIAA Journal ◽  
1963 ◽  
Vol 1 (1) ◽  
pp. 148-158 ◽  
Author(s):  
STEVEN I. FREEDMAN ◽  
JOHN R. RADBILL ◽  
JOSEPH KAYE
Keyword(s):  
Boundary Layer ◽  
Laminar Boundary Layer ◽  
Gas Injection ◽  
Theoretical Investigations ◽  
Supersonic Laminar

scholarly journals Reducing Drag of Body by Adding a Plate

2018 ◽  
Vol 220 ◽  
pp. 07002 ◽  
Author(s):  
A. Frolov Vladimir ◽  
S. Kozlova Anna
Keyword(s):  
Boundary Layer ◽  
Circular Cylinder ◽  
Flat Plate ◽  
Laminar Boundary Layer ◽  
Separation Point ◽  
Theoretical Investigations

This paper focuses on theoretical investigations of the location of a separation point laminar boundary layer on the surface of a circular cylinder. The investigations were carried out by CFD software FlowSimulation. The displacement of the separation point on the surface of the circular cylinder is achieved by installing a flat plate in front of the cylinder parallel to the flow. It was found that the greatest displacement of the separation point to the back of the cylinder is possible when the chord of the plate equals to a quarter of the diameter of the circular cylinder. The flat plate allows not only to change the position of the separation point but also to reduce the drag by about 25%.

Oblique slot blowing into a supersonic laminar boundary layer

1976 ◽  
Vol 80 (3) ◽  
pp. 541-554 ◽  
Author(s):  
N. Riley
Keyword(s):  
Boundary Layer ◽  
Laminar Boundary Layer ◽  
Free Stream ◽  
Length Scales ◽  
Supersonic Laminar

The response of a supersonic laminar boundary layer is considered when fluid is blown obliquely into it from a slot in the boundary. The velocity and length scales associated with the slot blowing are chosen in such a way that the triple-deck theory of Stewartson (9) may be exploited. It is shown that, depending upon the blowing angle, there can be either a compressive or expansive interaction between the boundary layer and free stream upstream from the slot.

On slot injection into a supersonic laminar boundary layer

1973 ◽  
Vol 332 (1588) ◽  
pp. 1-22 ◽  
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Boundary Conditions ◽  
Pressure Gradient ◽  
Laminar Boundary Layer ◽  
Extreme Conditions ◽  
Numerical Work ◽  
Plate Length ◽  
Injection Region ◽  
Supersonic Laminar

The structure of a supersonic laminar boundary layer near a flat plate is examined when fluid is injected into it, normal to the surface, with velocity O (∊ 3 U * ∞ ) over a distance O (∊ 3 L). Here U * ∞ is the undisturbed velocity of the fluid, L is the plate length and ∊ -8 is a representative Reynolds number of the flow. It is found that the pressure rises upstream of the injection region and that in all the cases fully computed the blowing takes place in a favourable pressure gradient. Afterwards the pressure rises to its undisturbed value. Further incomplete studies suggest that in more extreme conditions, e. g. longer slots, the pressure gradient can be adverse just downstream of the start of the blow and that separation can even occur there. The analytical discussion rests heavily on the notion of the triple-deck, a subdivision of the boundary layer suitable for investigating its response to sudden changes in boundary conditions. Extensive numerical work is also required and the methods devised fail when the boundary layer separates at the onset of the blow. The relation between this type of injection and weak plate injection where the blowing velocity is O (∊ 4 U * ∞ ) and extends over a distance O ( L ) is also considered.

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.

Sign in / Sign up

Export Citation Format

Share Document