Experimental Investigation of Impact of Radial Deflecting Arrangement of Permeable Groyns on Maximum Scour Rate of Nose

Groyns are some structures which are constructed in flow path to protect the river bank. One of the most significant challenges in groyns operation is production of scour hole at the nose. In this study; new arrangement is proposed for permeable groyns and effect of this arrangement on maximum depth of scour hole at the nose of the groyn is investigated experimentally. Amount of permeability for the groyn is selected to be 40%. 60% and 80% and the experiments were performed in clear water. The Froude number is considered to be constant in all experiments and the depth of scour hole was measured with laser meter with an accuracy of 1 mm. Impact of number of groyns in each permeability was investigated as well. Then, behavior of groyns because of change of permeability and also maximum depth of produced scour hole in the situation of nose of groyn with various numbers of bars was compared. Result of experiments shows that between performed experiments for groyn with radial deflecting arrangement, the scour hole depth is minimum on permeability of 80% and groyn with seven bars.