Abstract
Two dimensional experiments with permeable groynes were carried out and theoretical analysis was tried in order to know functions of permeable groynes. We found the fact there are close connection among three factors of mean velocity (U1), permeable velocitythrough groyne (vQ) and separate length (L). vQ is depending on U1 - it takes two fold values correspoding to the same U1 under the certain condition for the porosity of groyne. On the other hand, increase of vQ. reduces L, and L is weakly related in U1.
