FOREWORD 

 By Dr. Frederick H. Todd 



This report is a wide-ranging account of the fundamentals of the potential flow of 

 frictionless fluids, and its value is greatly enhanced by the large number of actual examples 

 included in the text. It will be of great value both to the practicing engineer concerned with 

 fluid flows and to the student. 



Dr. Earle H. Kennard was formerly Chief Scientist in the Hydromechanics Laboratory at 

 the David Taylor Model Basin, and later head of its Structural Mechanics Laboratory. Through- 

 out his service at the Model Basin he devoted his efforts to the advancement of knowledge in 

 these fields and to the physics of underwater explosions. The value of his work in these 

 areas and in the associated one of structural vibration is well attested by the many papers 

 and reports which he has published. 



He has also devoted much time to the education and training of the younger members of 

 the staff. His educational work, indeed, began much earlier as a professor at Cornell Univer- 

 sity, and unnumbered students have profited from his well-known text book on physics. 



His colleagues have learned to respect his judgements, to enjoy his friendship and to 

 appreciate his wit, even though it is sometimes somewhat sharp! 



This report is a typical example of Earle Kennard's clear, explanatory writing, com- 

 bined nevertheless with an admirable economy of words. It is a great pleasure to his many 

 friends and admirers to see it published while Dr. Kennard, though over 80 years of age, 

 is still active and still continuing to work in the field of structural vibration. We look for- 

 ward to the privilege of making more of his work available to the profession of naval archi- 

 tecture through the medium of Model Basin reports, for it is upon such people as Dr. Kennard 

 and the results of their research that the reputation and image of the establishment depends. 



