396 



Table 114 



TERMINAL VELOCITY OF FALL FOR DISTILLED WATER DROPLETS 



IN STAGNANT AIR 1 



Pressure, 760 mm. Hg., temperature, 20 °C, relative humidity, 50 percent. 



R j , , (air density) (equivalent drop diameter) (measured velocity) 



(viscosity) 

 8 (accel. of gravity) (air density) (mass of drop) 

 7r(viscosity) 2 (Reynolds number)* 

 Equivalent drop diameters are calculated from the mass. 



Equivalent 



drop 

 diameter 



Drag coefficient : 



0.01* 



0.02 



0.03 



0.04 



0.05 



0.06 

 0.07 

 0.08 

 0.09 

 0.10 



0.12 

 0.14 

 0.16 

 0.18 

 0.20 



0.22 

 0.24 

 0.26 

 0.28 

 0.30 



0.32 

 0.34 

 0.36 

 0.38 

 0.40 



0.42 

 0.44 

 0.46 

 0.48 

 0.50 



Terminal 



velocity 



cm. sec. -1 



27* 



72 

 117 

 162 

 206 



247 

 287 

 327 

 367 

 403 



464 

 517 

 565 

 609 

 649 



690 

 727 

 757 

 782 

 806 



826 

 844 

 860 

 872 

 883 



892 

 898 

 903 

 907 

 909 



0.52 912 



0.54 914 



0.56 916 



0.58 917 



* Drops with diameters less than 0.008 cm. obey Stokes' Law. 



1 Gunn, R., and Kinzer, G. D., Journ. Meteorol., vol. 6, p. 243, 1949. 



SMITHSONIAN METEOROLOGICAL TABLES 



