抄録
Linearized friction coefficient was examined experimentally for permeable breakwaters with precast concrete armour unit in shallow water region. The equation proposed by Sollitt et.al. was applied for calculating the friction coefficient from transmission coefficient. The friction coefficients obtained were less than 14 and varied with following parameters: ratio of incident wave height to block scale, HI/d, ratio of breakwater's width to wave length, B/L and wave steepness, HI/L. The parameter HI/d strongly affected the friction coefficient. The friction coefficient varied in the small range of 0 to 4 when the Reynolds number, ud/ v, was greater than 3×104.
