Department Technical Acoustics (AS-TEA)

Braunschweig

Acoustic test at original A320 wing in DNW-LLF
.
Acoustics windtunnel Braunschweig AWB, directional microphone array
.
Large-scale high lift model in DNW-LLF + CAA simulation
Noise-driven alternative aircraft configuration
.
Turbulence related sound radiation of slat (CAA simulation)
.

Distribution of sound sources for jet-flap interference

Acoustic test of installed propeller in DNW-NWB
.
Reduction of jet-related fuselage pressure fluctuations due to acoustic refraction at fuselage boundary layer during cruise conditions.
.

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
  • Investigation of acoustic (radiation-) installation effects at complete aircraft
  • Analysis and reduction of installation related aerodynamic sound generation at aircraft components, e.g.  (contra rotating) propellers in non-uniform flow and jet-flap interference
  • acoustic wind tunnel and flyover tests for the investigation of sources and validation of noise reduction technologies as well as of numerical simulations
  • Operation of  the Acoustic Windtunnel Braunschweig AWB and development of aeroacoustic wind tunnel corrections
  • Development, validation and application of numerical prediction methods for sound generated aerodynamically
  • Development of semi-empirical models for airframe noise sources (method PROFAN)
  • Experimental and numerical analysis as well as modeling of aerodynamic and acoustic, i.e. boundary layer and engine related excitation of fuselage pressure fluctuations at cruise conditions (sources of cabin noise)
  • Noise prediction and reduction for wind turbines

 

Research tools (in-house):

AWB
Aeroacoustic Windtunnel 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 solution of unsteady perturbations about RANS flow field on block structured grids (high resolution Finite Differences) for the computation of sound generation and sound propagation in flows up to near farfield.

DISCO(++)
CAA Code for the solution of unsteady inviscid perturbations about RANS flow field on unstructured grids (discontinuous Galerkin) for the computation of sound generation and sound propagation in flows up to near farfield.

(F)RPM
Advanced RANS data based stochastic 4D turbulence reconstruction for highly efficient simulation of turbulence related sources of sound and turbulent scattering.

APSIM
Ffowcs-Williams & Hawkings (incl. extensions) 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.

FMBEM
Fast Multipole boundary element method for the highly efficient solution of the wave equation on unstructured (triangular elements) surface grids.

Structure of branch:

Team lead noise reduction technologies:
Dr.-Ing. Michaela Herr

Team lead aeroacoustic testing:
Dipl.-Ing. Michael Pott-Pollenske

Team lead simulation technologies:
Dr.-Ing. Roland Ewert


Contact
Prof.Dr. Jan Werner Delfs
German Aerospace Center

Institute of Aerodynamics and Flow Technology
, Technical Acoustics
Tel: +49 531 295-2170

Fax: +49 531 295-2320

E-Mail: Jan.Delfs@dlr.de
Cornelia Delfs
German Aerospace Center

Institute of Aerodynamics and Flow Technology
, Technical Acoustics
Tel: +49 531 295-2171

Fax: +49 531 295-2320

E-Mail: Cornelia.Delfs@dlr.de
URL for this article
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Texte zu diesem Artikel
Lectures in Aeroacoustics (http://www.dlr.de/as/en/desktopdefault.aspx/tabid-191/401_read-22566/usetemplate-print/)
Friendcopter Datenwörterbuch (http://www.dlr.de/as/en/desktopdefault.aspx/tabid-191/401_read-12344/usetemplate-print/)