FluidModel.py 文件源码

def FF_Yang_Dou_residual(vbyu, *args):
    """
    The Yang_Dou residual function; to be used by numerical root finder
    """
    (Re, rough) = args

    Rstar = Re / (2 * vbyu * rough)
    theta = np.pi * np.log( Rstar / 1.25) / np.log(100 / 1.25)
    alpha = (1 - np.cos(theta)) / 2
    beta = 1 - (1 - 0.107) * (alpha + theta/np.pi) / 2
    R = Re / (2 * vbyu)

    rt = 1.
    for i in range(1,5):
        rt = rt - 1. / np.e * ( i / factorial(i) * (67.8 / R) ** (2 * i))

    return vbyu - (1 - rt) * R / 4. - rt * (2.5 * np.log(R) - 66.69 * R**-0.72 + 1.8 - (2.5 * np.log(
        (1 + alpha * Rstar / 5) / (1 + alpha * beta * Rstar / 5)) + (5.8 + 1.25) * (alpha * Rstar / (
        5 + alpha * Rstar)) ** 2 + 2.5 * (alpha * Rstar / (5 + alpha * Rstar)) - (5.8 + 1.25)
        * (alpha * beta * Rstar / (5 + alpha * beta * Rstar)) ** 2 - 2.5 * (alpha * beta * Rstar / (
        5 + alpha * beta * Rstar))))