16100lectre22_cg

16100lectre22_cg - Integral Boundary Layer Equations...

This preview shows pages 1–3. Sign up to view the full content.

Integral Boundary Layer Equations Displacement Thickness The displacement thickness * δ is defined as: * 00 11 ee e compressible incompressible flow flow uu dy dy ρ ∞∞  =−   ∫∫ ±²²³²² ´± ² ²³²²´ The displacement thickness has at least two useful interpretations: Interpretation #1 0 0 (1) e u dy u dy = = A A+B So, the difference is in area B . * “represents” the decrease in mass flow due to viscous effects, i.e. lost * e e visc u m = µ y u / u e u / u e (y) A B

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Integral Boundary Layer Equations 16.100 2002 2 Interpretation #2 Conservation of mass: 11 1 1 00 0 0 () 1 yy y e ee y y e u dy udy udy yu yu u u dy u yd y u +∆ = =+ ⇒∆ =  ∆=   ∫∫ Taking the limit of 1 y gives * 0 1 e u y u δ ⇒∆ = = So, the external streamline is displaced by a distance * away from the body due to viscous effects. Outer flow sees an “effective body” s tre am line y δ *(x) y y 1 u(y) x u e
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/06/2011 for the course AERO 100 taught by Professor Willcox during the Fall '03 term at MIT.

Page1 / 5

16100lectre22_cg - Integral Boundary Layer Equations...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online