Predict aeroacoustic noise in unsteady flows
Aeroacoustics involves the generation of acoustic noise by unsteady flows. This includes noise generated by jets, complex shear layers and flow over rigid structures.
  • Sunroof buffeting and acoustical impedance of flexible structures : the noise associated with sunroof buffeting is caused by unsteady flow over the sunroof opening interacting with the roof panel and radiating sound to the vehicle occupants.
  • Aeroacoustics on HVAC system : vibro-acoustics and aero-acoustics can be combined to model complex aero-vibro-acoustics problems such as those encountered in HVAC systems.
  • Transient aeroacoustics simulation on landing gear.
  • Aero-acoustic analysis offers insight into the noise emissions due to turbulent flow and the interaction of aerodynamic forces with the aircraft structure. Depicted here is an LES analysis of a leading edge flap for aero-acoustics.
  • Vortex Shedding from Landing Gear for Acoustics
  • wave6 is a standalone frequency domain simulation software package for modeling the transmission of noise and vibration through complex systems across a broad frequency range.It was developed in conjunction with wave six and combines CD-adapco’s expertise in flow simulation with wave six’s knowledge of noise and vibration simulation.

STAR-CCM+ includes an extensive library of aeroacoustic methods for predicting the sources of aeroacoustic noise.  These range from steady state methods through to full direct simulation using DES, LES and near and far field propagation.  The methods can also be combined with wave6  for modeling aeroacoustic installation effects and flow induced noise and vibration transmission.

Steady State Models

Steady state models can be used early in the design process to quickly identify possible sources of noise. STAR-CCM+ provides the Curle, Proudman and Goldstein axisymmetric noise source models which may be used in RANS simulations. The Linearized Euler equation (LEE) and Lilley noise source model are available for synthesized fluctuations - stochastic noise generation and radiation (SNGR).  The steady state models also include functionality for estimating mesh cut-off frequencies in order to identify areas where additional mesh refinement may be needed.

Direct Models

STAR-CCM+ can be used to accurately model the sources of noise in unsteady flows modeled with DES and LES.  This includes both accurate prediction of the convective turbulence that generates the noise along with methods for propagating that noise in the near field (using compressible CFD or using incompressible CFD along with the newly developed time domain Acoustic Wave Equation solver in STAR-CCM+).  STAR-CCM+ also includes functionality for identifying aero-acoustic noise sources on permeable or impermeable surfaces in the time domain using the inbuilt Ffowcs Williams-Hawkings (FWH) acoustic models.  Advanced signal processing functionality is also included for diagnosing the sources of noise in flow including Fast Fourier transforms (FFTs) to analyze frequency and wavenumber content, inverse FFTs, band pass filters, auto-spectra and cross-spectra.

Propagation Models

STAR-CCM+ includes functionality for propagating aeroacoustic noise sources on permeable and impermeable surfaces to far field receiving locations using the inbuilt time domain FWH methods.  For problems which involve scattering and diffraction of acoustic waves or transmission of flow induced noise and vibration through complex vibro-acoustic systems it is also possible to extend the functionality in STAR-CCM+ using the frequency domain methods in wave6


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