Source code for RCAIDE.Library.Methods.Noise.Frequency_Domain_Buildup.Rotor.TIP_broadband_noise
# RCAIDE/Methods/Noise/Frequency_Domain_Buildup/Rotor/TIP_broadband_noise.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 TIP Broadband Noise
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[docs]
def TIP_broadband_noise(alpha_tip,M,c,c_0,f,Dbar_h,r_e):
'''This computes the tip noise 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:
alpha_TIP - angle of attack of tip section [deg]
M - Mach number [-]
c - airfoil section chord [m]
c_0 - speed of sound [m/s]
f - frequency spectrum [Hz]
Dbar_h - high frequency directivity term [-]
r_e - distance from noise source to observer [m]
Outputs
SPL_TIP - Sound pressure level of tip [dB]
Properties Used:
N/A
'''
l_div_c = 0.023 + 0.0169*alpha_tip # eqn 67 BPM Paper
l_div_c[2<alpha_tip] = 0.0378 + 0.0095*alpha_tip[2<alpha_tip]
l = l_div_c*c # eqn 63 BPM Paper
M_max_div_M = (1 + 0.036*alpha_tip) # eqn 64 BPM Paper
M_max = M_max_div_M * M # eqn 64 BPM Paper
U_max = c_0*M_max
St_prime_prime = f*l/U_max # eqn 62 BPM Paper
SPL_TIP = 10*np.log10(((M**2)*(M_max**3)*(l**2)*Dbar_h)/(r_e**2)) - 30.5*(np.log10(St_prime_prime + 0.3))**2 + 126 # eqn 61
return SPL_TIP
