Interference pattern of wave energy versus y at two distances x from the generator with β=−π/4. The integrand in (3.5) gives the wave power behind the wave energy converter (WEC) as a function of the transverse distance y. The lower black curve gives the net power at some arbitrary distance x behind the WEC, whereas the lower dashed line shows the original wave power. There is a decrease in the centre and interference fringes on both sides. If the distance from the WEC is doubled, then we get the upper two lines. The corresponding original wave power (dashed line) is the same as before but both these lines have been displaced upwards for clarity. With x increased by the factor 2, the amplitude of the interference pattern is reduced by the factor , but it is stretched sideways by the same factor; the total energy subtracted from the wave is unchanged.