What is self-similar flows?
Self-similar flows are admissible solutions of the Navier-Stokes equations in unbounded domains, and in applications it is assumed that the effects of the boundary conditions at the edge of the domain will have only a local effect and that a self- similar solution will be valid in most of the fluid domain.
What is the main assumption of boundary layer theory?
(i) Away from the surface of the object, viscous effects can be considered negligible, and potential flow can be assumed. (ii) In a thin region near the surface of the object, called the boundary layer, viscous effects cannot be neglected, and are as important as inertia. 2.
What is Prandtl boundary layer theory?
Prandtl introduced boundary layer theory in 1905 to understand the flow of a slightly viscous fluid near a solid boundary. Prandtl’s boundary layer theory is the original, and fundamental, example of a singular perturbation problem that can be treated by the method of matched asymptotic expansions.
What is meant by the idea of self similarity?
In mathematics, a self-similar object is exactly or approximately similar to a part of itself (i.e., the whole has the same shape as one or more of the parts). Many objects in the real world, such as coastlines, are statistically self-similar: parts of them show the same statistical properties at many scales.
What is the importance of boundary layer theory?
Engineers call this layer the boundary layer because it occurs on the boundary of the fluid. The details of the flow within the boundary layer are very important for many problems in aerodynamics, including wing stall, the skin friction drag on an object, and the heat transfer that occurs in high speed flight.
What are the characteristics of boundary layer?
Boundary layers are thinner at the leading edge of an aircraft wing and thicker toward the trailing edge. The flow in such boundary layers is generally laminar at the leading or upstream portion and turbulent in the trailing or downstream portion.
What is meant by flow separation?
Flow separation or boundary layer separation is the detachment of a boundary layer from a surface into a wake. Separation occurs in flow that is slowing down, with pressure increasing, after passing the thickest part of a streamline body or passing through a widening passage, for example.