Falling velocity, crystal size, mass, cross-sectional area, crystal form, and degree of riming on snowflakes were measured at Toyama City in January-February 1994. The degree of riming was classified into three types. The falling velocity V was expressed as a function of mass which was de-duced from melted snoflake diameter
D, that is,
V=k
Dn, where k and n are constants but both increased with the intensity of riming. The falling velocity of densely-rimed snowflakes was expressed as
V=198D
0.23cm/s. The relation between densityσand average diameter d of densely-rimed snowflakes wasσ·d
0.81=0.027(cgs unit), while that obtained by Magono and Nakamura (1965) wasρ·d
2=0.02. When Reynolds numbers were between 300 and 2500, drag coefficients of snowflakes were in a range of 0.4 to 1.3;the small value is nearly equal to that of sphere and the large value is to that of a cylinder. The drag coeffcient slightly decreased with the increase of Reynolds numbers. It was found that k and n depend on the relationship between drag coefficients and Reynolds numbers and on mass-dimension relationship of snowflakes.
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