Source code for RCAIDE.Library.Methods.Aeroacoustics.Semi_Empirical.Airframe.landing_gear_noise
# RCAIDE/Methods/Aeroacoustics/Semi_Empirical/Airframe/clean_wing_noise.py
#
#
# Created: Jul 2023, M. Clarke
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# IMPORT
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import numpy as np
from RCAIDE.Framework.Core import Units
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# main and nose landing gear noise
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[docs]
def landing_gear_noise(D, H, wheels, M, velocity, phi, theta, distance, frequency):
"""
This calculates the Landing gear 1/3 octave band sound pressure level and overall sound pressure level.
Parameters
----------
D : float
Landing gear tyre diameter.
H : float
Landing gear strut length.
wheels : int
Number of wheels per unit.
M : float
Mach number.
velocity : float
Aircraft speed.
phi : float
Azimuthal angle [rad].
theta : float
Polar angle [rad].
distance : float
Distance from airplane to observer, evaluated at retarded time [ft].
frequency : array_like
Frequency array [Hz].
Returns
-------
SPL : array_like
Sound Pressure Level of the landing gear [dB].
Notes
-----
The function uses correlation-based methods to compute the noise levels from the landing gear.
**Definitions**
'SPL'
Sound Pressure Level, a measure of the sound intensity.
References
----------
Fink, Martin R. "Noise component method for airframe noise." Journal of aircraft 16.10 (1979): 659-665.
"""
velocity_kts = velocity/Units.knots
if (wheels==1 or wheels==2):
G1 = 130
G2 = 10 *np.log10(4.5* ((frequency*D/velocity)**2) * (12.5 + ((frequency*D/velocity)**2) )**(-2.25) )
else:
G1 = 123
G2 = 10 *np.log10(0.3* ((frequency*D/velocity)**2) * (1 + 0.25*((frequency*D/velocity)**2) )**(-1.5) )
SPL = 60.*np.log10(velocity_kts/194.0)+20.*np.log10(D/distance)+ G1 + G2
return SPL
