RCAIDE.Library.Methods.Aeroacoustics.Semi_Empirical.Turbofan.turbofan_engine_noise

turbofan_engine_noise#

turbofan_engine_noise(microphone_locations, turbofan, aeroacoustic_data, segment, settings)[source]#

This method predicts the free-field 1/3 Octave Band SPL of coaxial subsonic jets for turbofan engines under various conditions.

Parameters:

microphone_locations (array_like) – Coordinates of the microphones used to capture noise data.
turbofan (RCAIDE type turbofan) –
Contains turbofan engine specifications.
- core_nozzleobject
  Contains attributes like exit_velocity and diameter.
- fan_nozzleobject
  Contains attributes like exit_velocity and diameter.
- heightfloat
  Engine centerline height above the ground plane.
- lengthfloat
  Length of the turbofan.
- diameterfloat
  Diameter of the turbofan.
- plug_diameterfloat
  Diameter of the engine external plug.
- geometry_xe, geometry_ye, geometry_Cefloat
  Geometric parameters for jet installation effects.
aeroacoustic_data (object) –
Contains aeroacoustic data for the turbofan.
- core_nozzleobject
  Contains attributes like exit_stagnation_temperature and exit_stagnation_pressure.
- fan_nozzleobject
  Contains attributes like exit_stagnation_temperature and exit_stagnation_pressure.
- low_pressure_spoolobject
  Contains angular_velocity.
segment (RCAIDE type segment) –
Contains flight path data and conditions.
- conditionsobject
  Contains freestream velocity, mach number, and speed of sound.
- framesobject
  Contains inertial time data.
settings (object) – Contains settings such as center frequencies for noise calculations.

Returns:

engine_noise –

Contains the computed noise data.

SPL_1_3_spectrumarray_like
One Third Octave Band SPL spectrum.
SPLfloat
Sound Pressure Level.
SPL_dBAfloat
A-weighted Sound Pressure Level.

Return type:

Data

Notes

The function uses semi-empirical methods for coaxial jet noise prediction. It accounts for various conditions such as flyover, static, and in-flight scenarios.

Major Assumptions

Coaxial subsonic jets
Free-field conditions

Theory

The noise prediction is based on the combination of primary, secondary, and mixed jet components, with adjustments for installation and environmental effects.

Definitions

‘SPL’: Sound Pressure Level, a measure of the sound intensity.

References

[1] SAE ARP876D: Gas Turbine Jet Exhaust Noise Prediction (original) [2] de Almeida, Odenir. “Semi-empirical methods for coaxial jet noise prediction.” (2008). (adapted)