T] A/^a- ^"id p^/srL NEW YORK UNIVERSITY INSTITUTE OF MATHEMATICAL SOfNCES LIBRARY 4 Waihington Place, New York 3, N, Y Diary of Trip to r.'sllforrla > Farch 8 - 31, 1947 Harold Grad Aerojet Corporation, Aguaa The nroblorns of Irref^ular burning and genoral hydro- dynawlc flow inside iiiultlplTf connected hollow tube rockets were r^lscussed with T*. ^. D, Geckler and A, L. Antonio, Secondary peak end Irregular burning phenoirena similar to those observed at California Institute of Technology durlnf? the war have been observed In both the hollow grain and the rod end tube dealpns used by Aerojet. T' ' " • The Interrupted burning techniques used are still beln/a? developed, but from a discussion of results already available it appears probable that the resonance burning hypothesis set forth by the New York TTniverslty group Is correct. The physical basis of the phenonenon together with the qualitative effects of various rocket design features were discussed. -2- Ir ordei* to verify certain aspects of the theory which h«a been develot)ed. It waa decided to Derforro exioerlTnenta on rockets of varying georretry and type of powder. Experiments involving direct observation of powder reaction rates and flow patterns Inalde the rocket are not feasible at present. According to "Dr. Geekler, it would be v/orthwhlle to reduce the irathematlcal solution to a forrri whereby the incidence of pressure peaks and irregular burning could be predicted in tenns of one or more parameters Involving the rocket eeometry and powder grain constants. In addition to the resonance burning oroblem, work done at New York TTnlverslty on flow In multiple channel rockets and on the validity of one dinenslonal treatments wts dis- cussed. T>r. Oeekler was also interested In heat +-ran8fer with variable coefficients, and requested inforrration on the work done by and under t^. ivacnonald on this subject. Some problerrs in nozzle flow were discussed with R. Gordon, in particular the calculation of thrust for an inexact exnanslon nozzle. A Tremorenduin on this subject will be sent to hire by Hew York TTniveraity. ■pjxperlTnents are being perforrred on rockets which have purely diverging noszlea (i.e. no converging entry section), ra^oek reflection natterns in the exhavist can be observed directly by eye, since the various regions in the exhaust are distinctively colored. Several probleins involving straipjit pipe ^et wotors were discussed with T5r. F, ?^Brlcl<T, who was interested in a Tnemo- randuK being written on this subject, and who suggested so^e possible lines of further development. He also expressed interest in a renort on the Pulse Jet by Wae Donald and sehaaf and requested a cony. -3- Dp. Tlwlcky, as well sa nun^erous other poraona encountered In California, la e8«j;erly airaltlng the oppearanoe of the revised Shook ?'eve I'nnual. JPL-APL Sym-posluw JPL - Jet Propulsion Laboratory - California Institute of Technolopy APL - Applied Physics Laboratory - Johns Hopkins University The sympositur consisted mainly of a discussion of free fli^t techniques and comparison with wind tunnel results. It appears that there ere no results at present which allow of direct coTTparlaon between the two rrethods. Certain anor.alouc droft effects are observed at transsonlc speeds, but different experiments vary widely in results. k novel method of measuring drag of a projectile in free fll^t using a so-called belllstlc pendulum was described. California Institute of Technology Dr. Hans LleTrann was consulted on his work on interactions between shock and viscous boundary layers. It appears that the very large velocity -radients in the neighborhood of a viscous boundary layer at a well produce shock reflection patterns which are entirely different froni what la predicted by simple ehock reflection theory, but it is expected that at sufficiently large distances from the wall the pattern may apTwoxlciate that of the slinple theory. Slmiler curved shock effects are found in I^ach reflectiona because of the large velocity gradients In the sllpstresn. These effects, together with Kiore complicated shock and boundary layer phenomena are found to be essential in describing transsonlc flow around an airfoil (which may be somewhat connected v'lth recent investigations In New York University). -4- Some proT?«rtle8 of llrit lines were discussed by Drs. Liepmerm and Cleuser at s lecture by the latter* Several Interesting probler.s eoncernlnf^ characteristics of hydrodynarnlc equations (with and without either heat conduction or viscosity); characteristics of lower order terms in parabolic equations; a comDarlaon of the equations of transient nozzle flow and waves on sloping beaches; some features of the Karwan-Moore perturbation method, end «n equation of rlxed elllr^tlc-hyperbolic character were dlacussed with Dr» D© Prima, Two water tunnels (one for rreasurenent of drag, lift, moment and one with a free surface at arbitrary air pressure), a centrifugal tornedo impact tank, and the tranasonic wind tunnel were visited. Other presons contacted on various matters are Professors Epstein and Bohnenblust, Autoratlc Computing? I'achines At California Institute of Technology Professor MeCann of the Electrical Engineering Department was consulted about the status of various computation developments on the coast, TTe is at present constructing an analogue differential analyzer, aimed principally at elastic beam and electrical system stability nroblerrs, which treats on the order of 100 linear ordinary differential eouations and some 10-20 nonlinear equations. There is a nosslbillty of a digital computer being constructed at California Institute of Tech-nology some time in the future. Various electromechanical simulators such as for torpedoes, guided missiles, etc. exist, and UCLA has a GE differential analyzer. Howard Hughes Aircraft is eonstrwetlni? various small specialized machines, and one larp;e digital machine (details secret) which Is nresvroably to solve !"'axwell'8 Equations. They have obtained some computing machine men from Bell Labs. Prom a consensus It appears thst the Bureau of Standards Institute of Numerical Analysis i-vlll probably be located at Stanford or Berkeley. According to the outspoken S, ^aymo. Director of Research at Howard Hucjies, the Bureau of standards* methods do not offer much chance for any development in larf^ scale computlnp; nachlnea other then a rehash of already exist Ini^ machines. Professors Spencer and Polya who were cortacted at Stanford are anxious to have the Bureau of Standards' Computing Center either there or at Berkeley. !5r. spencer has some problems on schllcht functions which involve large scale computations and for which he la thinking of usin^ the ?^iac. The nroblem of Ir.pact of a cone in water v;hlch is being put Into final form by Drs. Spencer and Shlffman was discussed, end some necessary liaison between the two was arranged. NEW YORK UNIVERSITY INSTITUTE OF MATHEMATICAL SaENCES LIBRARY 4 W»Ai.g;an Place,'i^^ York 3, N, Y ,'>«> a'rso'ii