RCAIDE.Library.Methods.Noise.Correlation_Buildup.Turbofan.turbofan_engine_noise

turbofan_engine_noise

turbofan_engine_noise(microphone_locations, turbofan, aeroacoustic_data, segment, settings)

This method predicts the free-field 1/3 Octave Band SPL of coaxial subsonic

jets for turbofan engines under the following conditions: a) Flyover (observer on ground) b) Static (observer on ground) c) In-flight or in-flow (observer on airplane or in a wind tunnel)

Assumptions:

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

Inputs:

vehicle - RCAIDE type vehicle includes these fields:

Velocity_primary - Primary jet flow velocity [m/s] Temperature_primary - Primary jet flow temperature [m/s] Pressure_primary - Primary jet flow pressure [Pa] Area_primary - Area of the primary nozzle [m^2] Velocity_secondary - Secondary jet flow velocity [m/s] Temperature_secondary - Secondary jet flow temperature [m/s] Pressure_secondary - Secondary jet flow pressure [Pa] Area_secondary - Area of the secondary nozzle [m^2] AOA - Angle of attack [rad] Velocity_aircraft - Aircraft velocity [m/s] Altitude - Altitude [m] N1 - Fan rotational speed [rpm] EXA - Distance from fan face to fan exit/ fan diameter [m] Plug_diameter - Diameter of the engine external plug [m] Engine_height - Engine centerline height above the ground plane [m] distance_microphone - Distance from the nozzle exhaust to the microphones [m] angles - Array containing the desired polar angles [rad]

Outputs: One Third Octave Band SPL [dB]

SPL_p - Sound Pressure Level of the primary jet [dB] SPL_s - Sound Pressure Level of the secondary jet [dB] SPL_m - Sound Pressure Level of the mixed jet [dB] SPL_total - Sound Pressure Level of the total jet noise [dB]