مقایسه روش‌های تحلیلی تجزیه امواج به منظور محاسبه ضریب انعکاس موج

Calculation of the reflected waves against obstacles is a prominent step in designing coastal structures. In addition, a complex process occurs during wave collision with beaches or breakwaters. These processes cause wave characteristics to be (energy dissipation, reflected wave, etc.). The new wave characteristics are dependent on reflected wave height straightly which are not measureable. In other words, finding an appropriate method for identifying reflected waves is an essential part of each marine project. In recent years analytical and experimental methods have been established for the decomposition of incident and reflected waves. An analytical solution for estimation of the reflection coefficient is time domain analysis. In this method, waves which radiate in opposite directions could be separated by zero crossing method. Alternative analytical way is using fast Fourier method which is called spectrum analysis. In this paper, above methods are compared by using experimental data. Two-dimensional experimental studies are carried out in the Hydraulic laboratory of Amirkabir University of Technology (Tehran, Polytechnic) to collect appropriate time series. Results reveal that although spectrum analysis, compared with time domain analysis, allocates higher wave height for both incident as well as reflected waves, reflection coefficients are virtually same in both methods. Furthermore, evaluated incident wave height in time domain analysis is close to wave height in wave maker theory.