Source code for RCAIDE.Library.Methods.Noise.Frequency_Domain_Buildup.Rotor.noise_directivities
# RCAIDE/Methods/Noise/Frequency_Domain_Buildup/Rotor/noise_directivities.py
#
#
# Created: Jul 2023, M. Clarke
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# IMPORT
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# Python Package imports
import numpy as np
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# Compute Noise Directivities
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[docs]
def noise_directivities(Theta_er,Phi_er,cos_zeta_r,M_tot):
'''This computes the laminar boundary layer compoment of broadband noise using the method outlined by the
Brooks, Pope and Marcolini (BPM) Model
Assumptions:
BPM models assumes a naca 0012 airfol
Source:
BPM Model: Brooks, Thomas F., D. Stuart Pope, and Michael A.
Marcolini. Airfoil self-noise and prediction. No. L-16528. 1989.
Inputs:
Theta_e - Radiation angle with respect to free stream x (chordwise) [rad]
Phi_e - Radiation angle with respect to free stream y (spanwise) [rad]
M_c - Convection Mach number [-]
M - Mach number [-]
Outputs
Dbar_h - high frequency directivity term [-]
Dbar_l - low frequency directivity term [-]
Properties Used:
N/A
'''
Dbar_h = (2*(np.sin(Theta_er/2)**2)*((np.sin(Phi_er))**2) )/((1 - M_tot*cos_zeta_r)**4) # eqn 20 Brooks & Burley
Dbar_l = ((np.sin(Theta_er)**2)*((np.sin(Phi_er))**2) )/((1 - M_tot*cos_zeta_r)**4) # eqn 19 Brooks & Burley
return Dbar_h,Dbar_l
