= aentie ETae - PROGRAM 10 Project 10.1 = Fireball Hydrodynamics - J. H. Mullaney - LASL 10.2 = Time of Arrival The object of Program 10.1 is the consideration of fluid dynamics of the fireball, for the purpose of estimating the yield of an explosion. This program does no experimental work of its own but relies on Program 15.1, Fireball Photography, by EG&G, for its input data. These input data are reduced through some scheme such as the analytic solution or Mach number scaling to give approximate yield. These methods are both somewhat similiar to the Phi to the 5th scaling method used by EG&G, Before Operation REDWING starts, Program 10.1 hopes to have finished, with the help of the Theoretical Division of this laboratory, a series of calculations done on the automatic computing machines. These calculations will attempt to describe the progress of a shock wave thru air starting at a time somewhat earlier than that used in ISM problem “M" which was done in this laboratory about 10 years ago. This new series of calculations will be done usingas realistic an equation of state of air as we can find and the series will cover a small range of densities of air. We hope to pick up whatever small departures exist from a simple atmospheric pressure and density scaling. The calculations should provide one other basis for scaling at least slightlydifferent from those currently in use. Some of the shots of this operation are rather low yield devices with relatively large associated masses, large shields, powder caps amd so on. in the past, shots with low yield to mass ratio have caused some trouble. Our data reduction interpretation procedures give yield determinations that are in good agreement with those given by radiochemistry for high yield devices, but when these same methods are used in a simple-minded fashion on low yield to mass devices the energy release figures are much higher than those given by radiochemistry. Program 10 again with the help of the Theoretical Division is trying to put mass effect work done in this laboratory some years ago in such form that it can be used in the field. a . DELETED DELETED : DELETED wave. ’ ED DELET DELETED _— DELETED The yield of the bomb can be estimated also from time of arrival of the shock Using hand-held stop watches, the interval between the flash and arrival of the shock wave can be measured, and then, through use of problem "M" listing, or ge _— — reams ciate ten hy — 4 _ month i