HARMONICS OF A WAVE

Abstract

In a hydraulics laboratory, waves are produced generally by a flap generator ; such a wave propagates in an open canal with a horizontal bottom and with a rectangular section. Because of the importance of its applications in practice, the detailed study of such a wave has a major interest. Considerable efforts are devoted, at present, to the production of a wave as pure as possible. Experience has shown, that in spite of all precautions taken, the wave is propagated always with some of its harmonics. It is useful to investigate analytically, on the basis of Stokes' linear theory, the conditions in which these harmonics originate. The conclusions of the theory presented here are not yet tested experimentally; it forms part of a programme of research of the laboratoire de Mdcanique des Fluides of the Institut Polytechnique of Grenoble. Most of the results presented here have been already published; a bibliography is given at the end of this article. It was thought desirable, however, to give a succinct review of the question, in the hope that it might be useful to the engineer.