RCAIDE.Library.Methods.Aeroacoustics.Semi_Empirical.Turbofan.external_plug_effect.external_plug_effect#

external_plug_effect(Velocity_primary, Velocity_secondary, Velocity_mixed, Diameter_primary, Diameter_secondary, Diameter_mixed, Plug_diameter, sound_ambient, theta_p, theta_s, theta_m)[source]#

This function calculates the adjustments, in decibels, to be added to the predicted jet noise levels due to external plugs in coaxial jets.

Parameters:

  • 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].

  • Diameter_primary (float) – Diameter of the primary jet [m].

  • Diameter_secondary (float) – Diameter of the secondary jet [m].

  • Diameter_mixed (float) – Diameter of the mixed jet [m].

  • Plug_diameter (float) – Diameter of the external plug [m].

  • sound_ambient (float) – Ambient sound level [dB].

  • theta_p (float) – Angle for the primary jet [rad].

  • theta_s (float) – Angle for the secondary jet [rad].

  • theta_m (float) – Angle for the mixed jet [rad].

Returns:

jet_plug_effects –

Contains the noise adjustments for each jet component.
  • PG_pfloat

    Adjustment for the primary jet [dB].

  • PG_sfloat

    Adjustment for the secondary jet [dB].

  • PG_mfloat

    Adjustment for the mixed jet [dB].

Return type:

Data

Notes

The function assumes that the external plug effect is significant for coaxial jets and calculates the noise adjustments accordingly.

Definitions

‘PG’

Plug Gain, the adjustment in decibels due to the presence of an external plug.

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)