In [ ]:
import numpy as np
h = 10 # Water depth.
k = 0.0611 # Wave number.
a = 1.3 # Lineaer amplitude.
# Coefficients.
A = k * a**2 / 4
B = 2 * (np.sinh(k * h))**2
C = np.cosh(k * h * (3 + B)) / np.sinh(k * h)**3
a2 = A * C
print("The second order amplitude is %2.3f m" % a2)