Hamid Houshangi - School of Civil Engineering, IUST, Tehran, Iran,
Abbas Yeganeh-Bakhtiary - Faculty of Engineering, UniversitiTeknologi Brunei (UTB), Brunei Darussalam
Abbas Yeganeh-Bakhtiary - School of Civil Engineering, IUST, Tehran, Iran
Ebrahim Jabbari - School of Civil Engineering, IUST, Tehran, Iran

Scour in front of vertical breakwaters (VBs) under the action of standing waves induces serious potential risks to the stability of such structures. The recorded history of theVBs confirms many failures due to occurrence of scour [1, 2]. The scour problem has been studied by many researchers, which indicate that the key mechanism forscour under action of standing waves in front of VBs is the field of steady streaming pattern, consisting of bottom and top re-circulating cells [3, 4]. Bed materials (bed sediment particles) essentially respond to the top and the bottom re-circulating cells; in which the fine and coarse materials are picked up respectively by the top and bottom cells. Coarse or fine materials may considerably influence on scour/deposition pattern in front of VBs and act on the stability of such structures.