def Hs_est(Hs_prime_est, harm_mean):
    """ Basic Equation: ((2*N_harmonic)/(2*N_harmonic-1))*Hs"""
    Hs = Hs_prime_est
    Hs_est = 2.0 * harm_mean / (2.0 * harm_mean - 1.0) * Hs
    return Hs_est
