12 



Appendix II 



A. Force on a cable normal to stream . 



If the stream velocity is V, the force per unit length will be of the form 



R =*kD£V a , k = k (RO (15) 



where D is the diameter of the cable, o is the density of the fluid, and k, a 

 non-dimensional coefficient, is a function of the Reynold's number R /= VDA ; . tf 

 is the kinematic viscosity. Table (6) gives values of k corresponding to values 



of R'in the range 105< R'< 10 6 . 



TABLE 6. 



R'x 10~ 5 .10 .20 1.0 1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 

 k 1.10 1.20 1.20 1.20 1.14 .94 .66 .33 .32 .32 .33 



B. Force on a cable tangential to stream . 



2 



The force per unit length is given by 



F = fTDpVA (2V/e + V) (16) 



where e = 2.62 x 10 ft. A depends upon the curvature and roughness of the 

 cylinder. Table (7) gives corresponding values of A and D for a smooth cylinder. 









TABLE 7. 









D( inches) 



00 



20.0 



10. 5. 



2.5 



1.4 



0.7 



A x 10 3 



1.07 



1.14 



1.17 1.21 



1.26 



1.31 



1.36 



(1) Data due to YJieselsberger, 1922. 



(2) Kempf "On the Frictional Resistance of Surfaces of Various Forms" 1924, 

 Proceedings of the 1st International Congress for Applied Mechanics. 



