Boundary Lyer Theory

424 XV. Non-atearly boundary layers d. Experimental investigation of the starting procem 125
[Jpon comparing with cqn. (l5.45), it in seen that for equal values of dU/dz separation occurs
rarlirr whrn thr nlot.ion is startrd impulsively than whrn the acceleration is uniform.
ll. Illasius mlrtrlnt~rl t.wo fnrthcr t(.rrns of thr vxpansion, and with their aid the equation
for 1, is ohtninrd in Ihr following ~notlified form:
For t.ho c.:isc. of :i cylindrr whir11 is 111:iocxl symtnd.rically with respect Lo the direction of flow the
last tnrm v:~~~ishrs :I(. Ihc. clownsl rcwn sl.ngnnLion point, and we obtain
U(T, 1) = 1 ~(r) -- 2 6 1 sin
R '
wl~rrr? h clcnolcn 1.11~ c:ot~st:int :ircrlrration. I-lcnce
z dw 2b z
1 ) - - 2 b sin - ; -
R dz R-R'
'I'ho pint :I& \vhi(:Ii s