A model experiment is conducted for a water-exchanging breakwater caisson to confirm usefulness of the devices at the outlets of exchanging water in controlling jet flow. Inclined pipes installed inside the caisson wall show satisfactory performance without reduction of exchanging water quantity. On the other hand, hoods, which are attached to the outlets, obstruct the jet flow and reduce the exchanging water quantity, although they curve the jet flow noticeably. Theoretical consideration is satisfactorily done with respect to the effect of tide and incident wave height on transmission coefficient, assuming that pulsatingjet flow generates transmission wave.
