DNA 1240H-2 Z = 1000 ($5 1/6 » t¥ 60 Y z =|1000 + t_- 60 x 1009] (5 180 x 1/6 z = 2000(75} 1/6 = a 20 [* + re(75) YX 1/6 » 60<t<2h0 , t>2ho (17-3) The expressions for Z were suggested by inspection of data from Operations Wigwam and Hardtack. They are used here for all depths of burst in the ranges under consideration. Actually, of the two Hardtack shots considered, the shallow one (Umbrella) produced a somewhat higher base surge. One would expect that decreased burst depth for a given yield generally would result in increased surge height, ae long as the shot remained below the Near-Surface category. However, the scatter of height observations at each of the Hardtack shots is so great that no attempt has been made to scale height with yield or depth. D. Scaling of Base Surge Size Several dimensionless expressions are used in Ref. 49 base-surge radius R, (ft) at time t (sec). for scaling the For Very Shallow and Shallow bursts: R Rec = —3 tee “or /2 where R,. (dimensionless) is the scaled (or reduced) radius, Diya, (ft) is the maximm diameter of the colum of west produced on the surface, and tgc is scaled time in terms of (sec/ft-/©). ‘The maximum diameter of the water column, Dax, can be expressed in terms of yield Y (KT and/or scaled burst depth dgo. For Very Shallow bursts: Dex = 710 3 For Shallow Bursts: Duy = 377 Y/3 a,2/6 where d,, = a YL 3 . Ry For Deep and Very Deep bursts: Reo = 5 ; tee = Kowt/2 where Amax (ft), the maximum radius of the bubble produced by the burst, 17-46 ne ae ee 8 ee re