تعيين ضرايب بازتاب امواج نامنظم از موج شكن هاي شكل پذير با استفاده از نتايج مدل آزمايشگاهي

Experimental investigation and determination of reflection coefficients of irregular waves from reshaping breakwaters

In this research the effects of irregular Ware,s reflection from the reshaping rubblernound breakwaters were investigated. Reshaping breakwater is a kind of new breakwaters, which its initial profile is changed to a (S) shaped one after impacting of waves. Therefore, the relations related to reflection coefficients on conventional breakwaters cannot he used for this type of structure. Method of research was based on Experimental modeling. Experiments were done for multiple cross sections of reshaping breakwaters with three different slopes in the Soil Conservation and Watershed Management Research Institute (SCWMRI) wave Flume, during 2003 to 2004. The wave flume equipped with a modern DI-11 wave generation system, which contains paddle, power pack, hardware and software divisions. The hydraulic response that mentioned above, were investigated by changing the wave parameters such as significant wave height, mean and peak wave period and storm duration on the three structureʹs seaward slopes, equal to 1:1.25, 1:2.0, 1:2.5..IONSWAP wave spectrum was used in all experiments. The Armourc layer materials were included in three grading class (Dn85A/ Dn 15A=1.14,1.44,1.82) and a Range of structural notional permeability index Pe (1 <_ D,,, ! D,,,. 20) In order to changing structural geometry, wave properties and comparison between two scales (X =50,30) , 120 tests were done with 1000 to 6000 waves in this research. At the end, comparisons between the results of different scale factor were done. The experimental results were plotted as graphs showing the reflection coefficients versus the surf similarity parameter and dcepwater wave steepness. because the Iribarren number does not accurately describe the combined effects of slope and wave steepness, an improved and new tit to data can be achieved using multiple linear regression and nonlinear regression which results in some new empirical equations which has been presented in this research.