6 and B1 = 3.65 are obtained. By equalizing

equation (6) and equation (7), in which the function of coefficient A (eq.  (9)) has been included, with coefficients A1 and B1, selleck chemicals the empirical equation for estimating the reduction coefficient of the mean spectral wave period when crossing the submerged breakwater is obtained: equation(10) KR−T0.2=−0.3RcHm0−i+0.51××1280.6exp×3.65×Rc/Hm0−iRcL0.2−i2+0.87. The above equation is valid, provided that the following limitations are taken into account: maximum KR−T0.2=1;−1.6≤Rc/Hm0−i≤−0.5;−0.5≤Rc/L0.2−i≤−0.02;0.034≤Hm0−i/Ls−i≤0.091. The empirical model presented below was derived for an emerged smooth breakwater, based on measurements conducted by Van der Meer et al. (2000) in the wave channel of the Delft Hydraulics company. The measurements are given in Table 2, and the measured reduction coefficients of the mean spectral wave period K0.2R−TKR−T0.2, which depend on the relative submersion Rc/L0.2 − i are shown in Figure 7. For each measured KR−T0.2KR−T0.2, the values of parameter K click here   are estimated according to equation  (6). The ordered pairs (Rc/L0.2, K  ) are inserted into the diagram and the points presented in Figure 10 obtained. The function of the form equation  (7) should be fitted to the points, assuming that the coefficient A   = const, i.e. that it does not depend on the parameter Rc/Hm0−iRc/Hm0−i. In the case of an emerged breakwater, the coefficient B

  is defined differently than in the case of a submerged breakwater. In data for the emerged crown, the measured coefficient KR−T0.2KR−T0.2 is very close to the ordinate, with Rc/L0.2 = 0.003 and parameter Rc/Hm0=0.05Rc/Hm0=0.05.B   is determined provided that L0.2 → ∞ in equation  (7), so that the first term of equation  (7) tends to 0, and equation  (8) is obtained. By inserting the values Rc/Hm0−i=0.05Rc/Hm0−i=0.05 and measured values KR−T0.2~0.68KR−T0.2~0.68

( Figure 7) in equation  (8),B ≈ 1.35 is obtained. Equation  (7) with coefficient B = 1.35 is fitted to the points in Figure 10 so that coefficient A = 810.6 is obtained. By equalizing equation (6) and equation (7), into which the coefficients A = 810.6 and B = 1.35 are inserted, the empirical equation for estimating the reduction coefficient of the mean Calpain spectral wave period when crossing the emerged breakwater is obtained: equation(11) KR−T0.2=−0.3RcHm0−i+0.51×810.6RcL0.2−i2+1.35. The above equation is valid provided that the following limitations are taken into account: maximum KR−T0.2=1;0.05≤Rc/Hm0−i≤1.1;0.003≤Rc/L0.2−i≤0.06;0.043≤Hm0−i/Ls−i≤0.053, the first term of equation (11) can be a minimum [−0.3Rc/Hm0−i+0.51]=0.075−0.3Rc/Hm0−i+0.51=0.075. Figure 11 shows the verification of the empirical models for estimating the reduction coefficients of the mean spectral periods when waves cross the submerged and emerged breakwaters (eq. (10) and eq. (11)).