Flyover Simulations and Noise Scenarios- FLYO®

REGISTERED AT EUIPO ON 21/06/2019 under No.018017579

Main Features

  • 80 a/c types with total max. 200 noise sources
  • each monopole source characterised by LW(f) and DI(j,q)
  • > 100 flight paths, each max. 5,000 segments
  • > 80 a/c types per path, each with 3 possible time periods for operating (day/evening/ night) and individual velocity
  • max. 999 a/c per type on each path (approx. 8 Mio events per scenario)
  • transient operations (e.g., tilt-wing approach to vertiport)
  • max. 1,000,000 observer points (imported or pre-defined grid)
  • computation in Octaves (31.5 – 16,000 Hz) or 1/3-Octaves (20 Hz – 20,000 Hz)
  • A/B/C/D frequency weighting or linear SPL spectra
  • > 10 noise metrics implemented
  • program environment: Windows 10/11 or macOS 11

Main Output

  • Averaged SPL per a/c in scenario (spectral if no grid compuation)
  • Computation grid (geometry)
  • Level vs. Time per a/c type, path and obeserver (single events only)
  • Level vs. Time per noise source
  • Averaged SPL spectrum per a/c type for each path and oberver
  • Averaged SPL per path for each observer (spectral if no grid computation)
  • Averaged SPL for complete scenario for each observer (spectral if no grid computation)
  • SEL per a/c type on each path for each observer
  • Areas [km2] for SPL per a/c type, path, overall scenario and selected metrics < 20 dB, 20-30 dB, 30-40 dB … > 90 dB (grid/map computation)
  • Level (spectrum) vs. Time for each a/c type, each path at each observer
  • Flyover spectra for transient operations (e.g. full footpring of single aircraft)
  • Special metrics for overall scenario (including grid/map computations)
  • Loudness and Sharpness (single event at each observer)
  • Check file (for plausibility check of sound propagation for each source, path and observer)
  • Restart file
  • Log file

Examples: Noise map for greater Munich aera in the presence of UAM air traffic (left) and noise footprint for a tilt-wing airtaxi at a generic vertiport (right).

[Topografic map: Bayerische Vermessungsverwaltung –“, Creative Commons Namensnennung 3.0 Deutschland Lizenz (CC BY 3.0 DE)]

Aircraft Noise Source Modeling

The following sources and their components can be simulated using well-established semi-empiric methods:

Fan Noise

  • Inlet Broadband Noise
  • Inlet Tone Noise
  • Combination Tones
  • Aft Broadband Noise
  • Aft Tone Noise

Jet Noise

  • Small Scale Mixing Noise
  • Transitional/Intermediate-Scale Mixing Noise
  • Inner Stream Plug Separation Noise
  • Plug/Downstream Shock Noise
  • Outer Stream Shock Noise
  • Inner Stream (or Single Stream) Shock Noise

Airframe Noise

  • Clean wing
  • Clean vertical tail
  • Clean horizontal tail
  • Landing Gear Noise (Nose & Main LG, i.e., 2-wheel and 4-wheel)
  • Trailing Edge Flap Noise (single-, double, triple slotted)
  • Leading Edge Slat and Flap Noise

Propeller Noise

  • Tonal components
  • Broadband noise
  • Propeller with tilt angle

Helicopter Noise

  • Periodic rotational noise / steady and unsteady loading (for main and tail rotor)
  • Compressibility-induced profile and drag noise (main rotor)
  • Thickness noise (main rotor)
  • Blade vortex interaction (BVI) noise (main rotor)
  • Broadband boise noise (main and tail rotor)

All of the above listed noise sources can be exported directly into FLYO® formats for further computations.

Aircraft Noise Auralisation

Munich Aeroacoustics is currently testing an own auralisation tool, aiming to generate audio files with focus on UAM air-taxis.

The auralisation will be performed by using the flyover results from FLYO®.