Maintaining an Adequate Wave Amplitude

It is known that the use of wave filters causes a decrease in the amplitude of the genera ted wave. This disadvantage may constitute a source of trouble in certain tests" usually of a theoretical nature, in which it is desired to obtain waves of large steepness. In this case» it is necessary to intensify the wave after' it has traversed the filters ~
             Two methods. which can be applied separately or' simultaneously" have been investigated at the Dauphin Hydraulic Laboratory (Neyrpic) for several year so,

             The first method consists of installing downstream of the filters a convergent channel where the wave is intensified;

             The second method consists of raising the channel bed downstream of the filters', this has little effect on the wave amplitude (the amplitude even decreases in certain cases) but. shortening the wave length» finally increases the wave steepness.
             Thanks to such arrangements" . It should be noted, nevertheless, that the first ,method is used more generally than the second method, which makes it possible to obtain appreciable intensification of the waves only when the ratio of depth to wave length is sufficiently small"