Back

Send article to a friendPrint

Department Technical Acoustics (AS-TEA)

Department Technical Acoustics

Department Technical Acoustics

Aeroacoustic wind tunnel Braunschweig, directional array

Turbulence induced sound radiation of slat (CAA simulation)

The branch investigates the noise generation at aircraft and vehicles and develops noise reduction technologies. For this purpose, on the one hand numerical simulation codes are being developed and employed, on the other hand experiments are conducted in aeroacoustic wind tunnels as well as in flyover tests.

Main fields of research:

• Aeroacoustic analysis of noise sources and noise reduction of airframe noise from high lift systems and landing gears
• Development of semi-empirical source models for the noise computation of aircraft components for the overall airframe noise prediction method PROFAN
• Investigation of the modification of noise sources and sound radiation due to the installation at the aircraft (source and radiation related installation effects)
• Analysis and reduction of advanced propeller- and jet noise under installation conditions
• Computation of helicopter rotor noise and virtual flyover
• Design and flight validation of minimum noise flight procedures for helicopters
• Aeroacoustic experiment for source analysis/validation of noise reduction technologies and numerical simulation in aeroacoustic wind tunnel Braunschweig AWB and DNW-tunnels
• Prediction and measurement of noise generation and propagation in air condition duct systems
• Development of aeroacoustic wind tunnel corrections
• Development and application of aeroacoustic prediction methods
  • CAA (=Computational Aeroacoustics) simulation code PIANO
  • Ffowcs-Williams & Hawkings solver APSIM
  • Ray-Tracing Code SHADOW

Research tools:

AWB
Aeroacoustic Wind tunnel Braunschweig, cross section 1.2x0.8 m2, Umax="65" m/s, anechoic chamber, external pressure supply for jets and flow control, source localization with elliptic mirror and stationary or directional microphone array, free field microphones, wind tunnel balance, hot wire anemometry and PIV flow field measurement.

Wide area wireless ground microphone system
System of 30 remote controlled noise measurement stations equipped with max. 2 microphones each for the measurement of the directional sound radiation of aircraft as well as the direct measurement of noise contours.

PIANO
CAA Code for the numerical solution of inviscid perturbations about RANS flow fields for the computation of sound generation and sound propagation in flows. Advanced stochastic 4D turbulence modelling for highly efficient simulation of sound sources at aerodynamic geometry components (usually not for complete aircraft) and in the near farfield.

APSIM
Ffowcs-Williams & Hawkings (and Kirchhoff) solver for the computation of the sound radiation in uniform flow on the basis of unsteady CFD/CAA data on aerodynamic surfaces or source- enclosing closed fluid surfaces: usually for farfield prediction.

SHADOW
Ray-Tracer with diffraction correction due to Maggi/Rubinowitz for the computation of acoustic installation effects at complete aircraft geometries.

BEMPAR
acoustic boundary element code for triangulated surface meshes.