Rate of growth of a laminar boundary layer on a flat plate

The rate of increase of the boundary-layer thickness 6 may be found by integrating Eqn (7.67), after setting Л = 0 in Eqns (7.64b and c) and substituting for / and Q. Thus Eqn (7.67) becomes

d<5 Cf 140 /і dx~21~ 13 pU^d

Rate of growth of a laminar boundary layer on a flat plate

Therefore

whence

<52 _ 140 px

T = Upt^

The integration constant is zero if x is measured from the fore stagnation point where (5 = 0, i. e.

Подпись: (7.68)6 = 4.64jc/{Rex)in

The other thickness quantities may now be evaluated using Eqns (7.64a, b) with Л = 0. Thus

Подпись: (7.69) (7.70) 6* = 0.375(5 = 1.74л /{Rex)l/1 6 = 0.139(5 = QM6x/{Rex)1/2