PREFACE 



The Seventh Symposium on Naval Hydrodynamics continues the policy, initi- 

 ated in the first of the series in 1956, of providing an international forum for 

 the presentation of research results and the exchange of scientific information 

 in that portion of hydrodynamics especially of naval and marine interest. 



In this spirit three major themes were selected for the technical program 

 of the Seventh Symposium: (a) unsteady propeller forces, a concentrated pres- 

 entation of the latest theoretical and experimental research results dealing with 

 time -dependent forces generated by marine propellers, (b) fundamental hydro- 

 dynamics, a sampling of advanced analytical results emphasizing numerical 

 techniques for solving a variety of basic hydrodynamic problems, and (c) uncon- 

 ventional propulsion, a wide-ranging discussion of a number of different propul- 

 sion schemes and devices other than conventional marine propellers. 



The international aspects of the symposium are reinforced by the distribu- 

 tion of nationalities among the authors and chairmen of the technical sessions, 

 by its location in the beautiful city of Rome, and by the joint sponsorship of the 

 Office of Naval Research, the Marina Militare Italiana,and the Istituto Nazionale 

 per Studi ed Esperienze di Architettura Navale with the collaboration of the 

 Consiglio Nazionale delle Ricerche. To these Italian organizations the Office of 

 Naval Research extends its gratitude and appreciation for their long and arduous 

 efforts which resulted in such superb arrangements for the Symposium. In par- 

 ticular, the encouragement and support of Gen. Isp. Giovanni Di Mento,Ten. Gen. 

 Alberto Alfano, and Ten. Gen. Antonio Siena are gratefully acknowledged. To 

 Col. Angelo Ferrauto and T. Col. Pier Giacomo Maioli, who bore the primary 

 responsibility for the detailed management of the Symposium and for the resolu- 

 tion of the innumerable day-to-day problems, go our limitless admiration, re- 

 spect, and appreciation for a demanding task magnificently executed. Our grati- 

 tude is similarly extended to Dr. Umberto Berni for his efficiency in managing 

 the fiscal aspects of the symposium. We are also deeply indebted to Gen. Isp. 

 Italo Battigelli, who, prior to his retirement from the Marina Militare Italiana, 

 initiated the discussions which led to the organization of the Seventh Symposium 

 on Naval Hydrodynamics. Mr, Stanley Doroff of the Office of Naval Research, 

 one of the principal contributors to the organization and management of this 

 series of Symposia almost from its inception, provided invaluable assistance in 

 his usual efficient and effective manner. 



Loi^Uaa — 



I^ALPH D. COOPER 

 Fluid Dynamics Program 

 Program Director 



m 



