# 邊界層分離

（重定向自气流分离

## 逆压梯度

${\displaystyle u{\partial u \over \partial s}=-{1 \over \rho }{dp \over ds}+{\nu }{\partial ^{2}u \over \partial y^{2}}}$

${\displaystyle dp/ds>0}$ 時，出現逆压梯度的現象，若逆压梯度夠大，會使得速度${\displaystyle u}$ 沿著流線${\displaystyle s}$ 減少，最後甚至可能變為零或負值[4]

## 影響邊界層分離的因素

${\displaystyle \rho u_{o}{du_{o} \over ds}=-{dp \over ds}}$

${\displaystyle {{\left.{\frac {{\text{d}}u}{{\text{d}}s}}\right|}_{y=0}}=0}$  并且 ${\displaystyle {\frac {{{\partial }^{2}}u}{\partial x\partial y}}<0}$

## 腳註

1. ^ Anderson, John D. (2004), Introduction to Flight, Section 4.20 (5th edition)
2. ^ Clancy, L.J., Aerodynamics, Section 4.14
3. Wilcox, David C. Basic Fluid Mechanics. 3rd ed. Mill Valley: DCW Industries, Inc., 2007. 664-668.
4. ^ Balmer, David. "Separation of Boundary Layers." School of Engineering and Electronics. 2 December 2007. University of Edinburgh. 12 March 2008 <http://www.see.ed.ac.uk/~johnc/teaching/fluidmechanics4/2003-04/fluids14/separation.html 页面存档备份，存于互联网档案馆>
5. ^ Fielding, Suzanne. "Laminar Boundary Layer Separation." 27 October 2005. The University of Manchester. 12 March 2008 <http://www.maths.manchester.ac.uk/~suzanne/teaching/BLT/sec4c.pdf[失效連結]>.