(SDR) ( ).
( ), (, , , ..) : SDR=SDR +SDR +SDR ,
SDR ; +SDR , SDR . SDR , Re
R =V*d/n=Q/(n*d) (2.19)
V , /;
n , 2 /. ( 1 2 / =106 ).
f, 2 V=Q/f, /c; Q , 3 /;
d , ; n , 2 /c
Re <=R.. ;
Re > R. . R , . 2.11. [5]
2.11.
R | |
, | 2100-2300 1800-2000 550-750 20-100 |
:
DR =l*r*l*V2 /(2d), , (2.20)
l ;
l =75/ Re ; l =0.3164*Re-0.25 . r , /3 (*2 /4 ); l , , d , .
( )
DR =r* x*b*V2 /2, , (2.21)
;
V , /.
b , . R >= 2300 b =1. R <2300 b .2.8.
. :
900 =2;
=0.8...0.9;
=0.9...1.2.
[4, 5]. . , h =0.85...0.9.