Source code for RCAIDE.Library.Methods.Aeroacoustics.Semi_Empirical.Turbofan.noise_source_location
# RCAIDE/Methods/Aeroacoustics/Semi_Empirical/Engine/noise_source_location.py
#
#
# Created: Jul 2023, M. Clarke
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
# RCAIDE imports
from RCAIDE.Framework.Core import Data
# Python package imports
import numpy as np
# ----------------------------------------------------------------------------------------------------------------------
# Noise Source Location
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def noise_source_location(B, Xo, zk, Diameter_primary, theta_p, Area_primary, Area_secondary, distance_microphone,
Diameter_secondary, theta, theta_s, theta_m, Diameter_mixed, Velocity_primary, Velocity_secondary,
Velocity_mixed, Velocity_aircraft, sound_ambient, Str_m, Str_s):
"""
This function calculates the noise source location for primary, secondary, and mixed jet components.
Parameters
----------
B : array_like
Array for storing intermediate calculations.
Xo : float
Initial position offset.
zk : float
Scaling factor for jet source location.
Diameter_primary : float
Diameter of the primary jet [m].
theta_p : array_like
Angles for the primary jet [rad].
Area_primary : float
Area of the primary jet [m^2].
Area_secondary : float
Area of the secondary jet [m^2].
distance_microphone : float
Distance from the noise source to the microphone [m].
Diameter_secondary : float
Diameter of the secondary jet [m].
theta : float
General angle used in calculations [rad].
theta_s : array_like
Angles for the secondary jet [rad].
theta_m : array_like
Angles for the mixed jet [rad].
Diameter_mixed : float
Diameter of the mixed jet [m].
Velocity_primary : float
Velocity of the primary jet [m/s].
Velocity_secondary : float
Velocity of the secondary jet [m/s].
Velocity_mixed : float
Velocity of the mixed jet [m/s].
Velocity_aircraft : float
Velocity of the aircraft [m/s].
sound_ambient : float
Ambient sound level [dB].
Str_m : array_like
Strouhal number for the mixed jet.
Str_s : array_like
Strouhal number for the secondary jet.
Returns
-------
source_location : Data
Contains the calculated angles for each jet component.
- theta_p : array_like
Angles for the primary jet [rad].
- theta_s : array_like
Angles for the secondary jet [rad].
- theta_m : array_like
Angles for the mixed jet [rad].
Notes
-----
The function iteratively calculates the source location for each jet component by adjusting angles and positions based on geometric and velocity parameters.
**Definitions**
'theta_p', 'theta_s', 'theta_m'
Angles for the primary, secondary, and mixed jet components, respectively.
References
----------
None
"""
# P rimary jet source location
XJ = np.zeros(24)
for i in range(24):
residual = Diameter_primary
XJ[i] = (zk*Diameter_primary)*(4.+4.*np.arctan((18.*theta_p[i]/np.pi)-9.)+(Area_secondary/Area_primary))
B[i] = (1./np.sin(theta))*(((Xo+XJ[i])/distance_microphone)+np.cos(theta))
if (B[i]>=0.):
theta_p[i]=np.arcsin(((B[i])**2.+1.)**(-0.5))
else:
theta_p[i]=np.pi-np.arcsin(((B[i])**2.+1.)**(-0.5))
XJ[i] = (zk*Diameter_primary)*(4.+4.*np.arctan((18.*theta_p[i]/np.pi)-9.)+(Area_secondary/Area_primary))
while residual>(Diameter_primary/200.):
XJ_old = XJ[i]
theta1 = theta_p[i]
B[i] = (1./np.sin(theta))*(((Xo+XJ[i])/distance_microphone)+np.cos(theta))
if B[i]>=0.:
theta_p[i] = np.arcsin(((B[i])**2.+1.)**(-0.5))
else:
theta_p[i] = np.pi-np.arcsin(((B[i])**2.+1.)**(-0.5))
theta2 = theta_p[i]
theta_p[i] = (theta1+theta2)/2.
XJ[i] = (zk*Diameter_primary)*(4.+4.*np.arctan((18.*theta_p[i]/np.pi)-9.)+(Area_secondary/Area_primary))
residual = np.abs(XJ_old-XJ[i])
# Secondary jet source location
residual = Diameter_secondary
XJ_old = 0.0
XJ[i] = (zk*Diameter_secondary)*(2.+1.6*np.arctan((4.5*theta_s[i]/np.pi)-2.25))*(1.+0.5/np.sqrt(Str_s[i])) \
* np.sqrt(1.+(0.7*Velocity_secondary/sound_ambient))*(Velocity_secondary/(Velocity_secondary-Velocity_aircraft))
B[i] = (1./np.sin(theta))*(((Xo+XJ[i])/distance_microphone)+np.cos(theta))
if B[i]>=0.:
theta_s[i] = np.arcsin(((B[i])**2.+1.)**(-0.5))
else:
theta_s[i] = np.pi-np.arcsin(((B[i])**2.+1.)**(-0.5))
XJ[i] = (zk*Diameter_mixed)*(2.+1.6*np.arctan((4.5*theta_s[i]/np.pi)-2.25))*(1.+0.5/np.sqrt(Str_s[i]))* \
np.sqrt(1.+(0.7*Velocity_secondary/sound_ambient))*(Velocity_secondary/(Velocity_secondary-Velocity_aircraft))
while residual>(Diameter_mixed/200.):
XJ_old = XJ[i]
theta1 = theta_s[i]
B[i] = (1/np.sin(theta))*(((Xo+XJ[i])/distance_microphone)+np.cos(theta))
if B[i]>=0.:
theta_s[i] = np.arcsin((B[i]**2.+1.)**(-0.5))
else:
theta_s[i] = np.pi-np.arcsin(((B[i])**2.+1.)**(-0.5))
theta2 = theta_s[i]
theta_s[i] = (theta1+theta2)/2.
XJ[i] = (zk*Diameter_mixed)*(2.+1.6*np.arctan((4.5*theta_s[i]/np.pi)-2.25))*(1.+0.5/np.sqrt(Str_s[i]))* \
np.sqrt(1.+(0.7*Velocity_secondary/sound_ambient))*(Velocity_secondary/(Velocity_secondary-Velocity_aircraft))
residual = np.abs(XJ_old-XJ[i])
#Mixed jet source location
residual = Diameter_mixed
XJ_old = 0.
XJ[i] = (zk*Diameter_mixed)*(3.+np.exp(-Str_m[i])+(2.+1.1*np.arctan((18.*theta_m[i]/np.pi)-13.))+ \
(1.+0.5/np.sqrt(Str_m[i])))*np.sqrt(0.5+0.5*Velocity_mixed/sound_ambient) * \
(Velocity_mixed/(Velocity_mixed-Velocity_aircraft))
B[i] = (1./np.sin(theta))*(((Xo+XJ[i])/distance_microphone)+np.cos(theta))
if B[i]>=0.:
theta_m[i] = np.arcsin(((B[i])**2.+1.)**(-0.5))
else:
theta_m[i] = np.pi-np.arcsin(((B[i])**2.+1.)**(-0.5))
XJ[i]=(zk*Diameter_mixed)*(3.+np.exp(-Str_m[i])+(2.+1.1*np.arctan((18.*theta_m[i]/np.pi)-13.))+\
(1.+0.5/np.sqrt(Str_m[i])))*np.sqrt(0.5+0.5*Velocity_mixed/sound_ambient) \
*(Velocity_mixed/(Velocity_mixed-Velocity_aircraft))
while residual>(Diameter_mixed/200.):
XJ_old = XJ[i]
theta1 = theta_m[i]
B[i] = (1./np.sin(theta))*(((Xo+XJ[i])/distance_microphone)+np.cos(theta))
if B[i]>=0.:
theta_m[i] = np.arcsin(((B[i])**2.+1.)**(-0.5))
else:
theta_m[i] = np.pi-np.arcsin(((B[i])**2.+1.)**(-0.5))
theta2 = theta_m[i]
theta_m[i] = (theta1+theta2)/2.
XJ[i] = (zk*Diameter_mixed)*(3.+np.exp(-Str_m[i])+(2.+1.1*np.arctan((18.*theta_m[i]/np.pi)-13.))+\
(1.+0.5/np.sqrt(Str_m[i])))*np.sqrt(0.5+0.5*Velocity_mixed/sound_ambient) \
*(Velocity_mixed/(Velocity_mixed-Velocity_aircraft))
residual = abs(XJ_old-XJ[i])
source_location = Data()
source_location.theta_p = theta_p
source_location.theta_s = theta_s
source_location.theta_m = theta_m
return source_location
