def compute_P_and_eff(aeroPower, ratedPower, Omega_rpm, drivetrainType,
drivetrainEff):
if not np.any(drivetrainEff):
drivetrainType = drivetrainType.upper()
if drivetrainType == "GEARED":
constant = 0.01289
linear = 0.08510
quadratic = 0.0
elif drivetrainType == "SINGLE_STAGE":
constant = 0.01331
linear = 0.03655
quadratic = 0.06107
elif drivetrainType == "MULTI_DRIVE":
constant = 0.01547
linear = 0.04463
quadratic = 0.05790
elif drivetrainType in [
"PM_DIRECT_DRIVE", "DIRECT_DRIVE", "DIRECT DRIVE"
]:
constant = 0.01007
linear = 0.02000
quadratic = 0.06899
elif drivetrainType == "CONSTANT_EFF":
constant = 0.00
linear = 0.07
quadratic = 0.0
else:
raise ValueError(
"The drivetrain model is not supported! Please check rotor_power.py"
)
Pbar0 = aeroPower / ratedPower
# handle negative power case (with absolute value)
Pbar1, dPbar1_dPbar0 = smooth_abs(Pbar0, dx=0.01)
# truncate idealized power curve for purposes of efficiency calculation
Pbar, dPbar_dPbar1, _ = smooth_min(Pbar1, 1.0, pct_offset=0.01)
# compute efficiency
eff = 1.0 - (constant / Pbar + linear + quadratic * Pbar)
eff = np.maximum(eff, 1e-3)
else:
# Use table lookup from rpm to calculate total efficiency
eff = np.interp(Omega_rpm, drivetrainEff[:, 0], drivetrainEff[:, 1])
return aeroPower * eff, eff
def compute_P_and_eff(aeroPower, ratedPower, drivetrainType, drivetrainEff):
if drivetrainEff == 0.0:
drivetrainType = drivetrainType.upper()
if drivetrainType == 'GEARED':
constant = 0.01289
linear = 0.08510
quadratic = 0.0
elif drivetrainType == 'SINGLE_STAGE':
constant = 0.01331
linear = 0.03655
quadratic = 0.06107
elif drivetrainType == 'MULTI_DRIVE':
constant = 0.01547
linear = 0.04463
quadratic = 0.05790
elif drivetrainType == 'PM_DIRECT_DRIVE':
constant = 0.01007
linear = 0.02000
quadratic = 0.06899
elif drivetrainType == 'CONSTANT_EFF':
constant = 0.00
linear = 0.07
quadratic = 0.0
elif drivetrainType == 'DIRECT DRIVE':
constant = 0.00
linear = 0.07
quadratic = 0.0
else:
exit(
'The drivetrain model is not supported! Please check servose.py'
)
Pbar0 = aeroPower / ratedPower
# handle negative power case (with absolute value)
Pbar1, dPbar1_dPbar0 = smooth_abs(Pbar0, dx=0.01)
# truncate idealized power curve for purposes of efficiency calculation
Pbar, dPbar_dPbar1, _ = smooth_min(Pbar1, 1.0, pct_offset=0.01)
# compute efficiency
eff = 1.0 - (constant / Pbar + linear + quadratic * Pbar)
else:
eff = drivetrainEff
return aeroPower * eff, eff
def hoopStressEurocode(d, t, L_reinforced, hoop):
"""default method for scaling hoop stress using Eurocode method
GB 06/21/2018: Ansys comparisons for submerged case suggests this over-compensates for stiffener
I'm not even sure the Eurocode is implemented correctly here. Suggest using the standard
hoop stress expression above or API's handling of ring stiffeners below.
"""
r = d / 2.0 - t / 2.0 # radius of cylinder middle surface
omega = L_reinforced / np.sqrt(r * t)
C_theta = 1.5 # clamped-clamped
k_w = 0.46 * (1.0 + 0.1 * np.sqrt(C_theta / omega * r / t))
k_w, _, _ = smooth_max(k_w, 0.65)
k_w, _, _ = smooth_min(k_w, 1.0)
return k_w * hoop