The line of separation of the three-dimensional boundary layer on an arbitrary curvilinear surface is a singular streamline on the body surface which separates the detachment region and which is a line of confluence for the limiting streamlines. Expressions are derived for the three-dimensional separation criteria on the basis of the condition of zero frictional force in the projection on the normal to the line of separation. The position of the line of separation is determined from the solution of an ordinary differential equation. An analysis is made of various cases of separation on the surface of a yawed cylinder and on the surface of sharp cones at an angle of attack in a supersonic stream. The position of the lines of separation is determined experimentally from the confluence of thin liquid films applied to the surface. It is shown that separation occurs on the sharp cone on the line z=π for values of the parameter K=−0.85.
KeywordsDifferential Equation Boundary Layer Ordinary Differential Equation Body Surface Liquid Film
- x, z
orthogonal curvilinear coordinates on surface
- h1, h2
coordinate along normal to surface
- α, β
coordinates associated with streamlines of ideal fluid
- h1′, h2′
corresponding (to α, β) Lamé coefficients
- u, w
velocity components along x and z axes
boundary layer thickness
angle between limiting streamline on surface and ideal fluid streamline
transverse curvature parameter on cone at angle of attack
conditions at body surface
conditions at edge of boundary layer.
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