longshore drift

剑桥词典

the movement of sand and small stones , etc. along the coast by waves travelling parallel or at an angle to the coast
沿岸漂移（海浪以與海岸平行的方曏，或以與其成一定角度的方曏運動，推動沙粒和小石子等沿著海岸前進） 返回 longshore drift