Seawalls are among protective structures that are constructed for decreasing the level of wave force and/or protecting from other structures. In this regard, more accurate investigation of these structures takes great importance from different perspectives. This research investigates the change of the velocity on seawall crown by considering the obstacles in different layouts and slopes. FLOW-3D has been used in this research for modeling. The results of the modeling show that the existence of obstacles has a determinative role in decreasing flow rate in the crown of seawalls. Also, as it was expected, the slope factor on upstream seawalls is very determinative in decreasing this rate such that the lowest velocity on the wall occurs in D-state layout and the slope of 45˚.

The aim of this study was to investigate the effect of an upstream slope and its roughness on the run-up level of waves. In this study, it was attempted to propose an appropriate and effective solution regarding the issue of wave run-up on seawalls through using a sloping seawall and examining the roughness on these slopes. The intended slopes for seawalls were 22, 27, 32, 39 degrees, respectively and had the roughness heights on wall surface were 15 cm, 20 cm and 30 cm. Moreover, four types of roughness layouts on the wall surface were investigated. The results, obtained from investigating the effect of slope and roughness on the run-up level of waves, were analyzed after drawing tables and figures. The results show that by increasing slope gradient of the structure, the run-up level also increases, thus, it can be concluded that the run-up level is directly correlated to the structure gradient. The highest run-up level is related to a diagram with a slope of 39 degrees and its lowest level is related to a slope of 22 degrees. Furthermore, the layout type 3 was recognized to be the best layout having the lowest run-up level. The results also revealed that the best and most efficient height for roughness is equal to 30 cm which has the lowest run-up level in all the slopes and layouts. Moreover, the impact of run-up was investigated according to the geometric shapes of layouts on the seawall surface and the results were presented.