= absolute viscosity of the fluid = b “” dg = d= da! 0.279 dt - 23| pe g Pi P-B p” = liwiting diame- ter to which the streamline law applies & = acceleration due to gravity The values for K,, Kp and were given as determined for irregular quartz perticles, which for this application is more suitable than those velues given for spherical particles. The v:lue of Ky was determined by solving the Eqs. E.] end #.2 at the point of transition (85 B) from streamline motion to the intermediate region.>/ The density of the oerticle was determinea experimentally for actual f:llout perticles collected in the field (see Section 5.4). The densityYof the air and the viscosityl3/or the air which is temperature aependent are shown in Table E.1. The values for the viscosity are based on temperature messurements ti.kken in the Bikini area at Shot l time by the Task Force eather Central, Temrercture data were not taken for altitudes above 50,000 ft, so the tempersture above that elevetion Wes acssimed to be isothermal. cince choice of the applicuble equation is dependent upon the type of motion experienced by particles fuelling through air, it was necessary to determine the limiting diameters to which the various laws apply. The expression for the liciting diameter to which the streamline law applies was given above, The expression for the intermediate region, ats ns) B P,(P-A) was availarle from another source.®/ The calculated values for the limiting varticle diameters at different altitudes for the two types of motion are :lotted in Fiz. E.1, These plots define the areas in which the vardovs equations for the uetermination of terminal velccities are appliceble, It is seen th:.t for some of the particle sizes considered (100, 150, 2% #) the terminal velocity calculaticns follow the intermediate law to the altitudes indicuted ond beyond th: t the ctreumline law. Also, for the purticle sizes considered from 250 to 1000 # in ditceter, it is evident thet the intermediate law only governs the terminal velocity determinations * when the density of the fluid is small as compcred to that of the perticle, the buoyancy correction becomes neplirsible and Eq. »,1 takes the forn, Ke Pp a Vn = p Since the temper ture above 50,000 ft was assumed to be isothermal, the viscority of the air remains coiust nt and the terminal velocity is pro- portional to the squsre of the diameter. 138 Thus for a given particle