Acoustic CFD (Computational Fluid Dynamics) analysis is a simulation method used to study the behavior of acoustic waves and sound propagation in fluid media (air, water, etc.). This analysis is used especially in engineering applications to understand how sound propagates, the effect of sound sources, and the effects of fluids on sound.

Basic Approaches Used in Acoustic CFD Analysis

Direct Simulation (DS)

  • Both fluid motion and acoustic waves are calculated using the full Navier-Stokes equations.
  • It gives extremely accurate results, but is usually used in small-scale problems due to its high computational cost.

Discrete Flow and Acoustic Approach (Hybrid CFD/CAA – Computational Aeroacoustics)

  • First, flow analysis is performed with CFD and the obtained flow data is used for acoustic simulation.
  • Lighthill’s Acoustic Wave Equation, Ffowcs Williams-Hawkings (FW-H) equation and similar models are used to calculate the propagation of sound.
  • It is preferred in large-scale and complex geometry systems.

Linearized Euler Equations (LEE)

  • The propagation of sound is calculated by considering fluid motion.
  • It is used to understand the propagation of sound waves, not the source of noise.

Where is Acoustic CFD Analysis Used?

Automotive Sector

  • Optimization of engine, exhaust systems and in-car sound insulation
  • Turbulence-induced noise analyses
  • Optimization studies on the silence of electric vehicles

Aviation and Space

  • Noise analyses of jet engines
  • Acoustic effects caused by wing turbulence
  • Sound propagation inside the aircraft cabin

Building Acoustics

  • Noise analysis of ventilation systems
  • Indoor acoustics and reverberation time optimization
  • Sound insulation and noise control

Electronic Devices

  • Analysis of noise levels of fan cooling systems
  • Speaker and microphone design

Software Used in Acoustic CFD Analysis

  • ANSYS Fluent – ​​Frequently used for fluid dynamics and acoustic analysis.
  • COMSOL Multiphysics – A powerful tool that combines acoustic and flow analyses.
  • OpenFOAM – Open source and includes customizable acoustic models.
  • SIEMENS Simcenter STAR-CCM+ – Performs flow and sound analysis in an integrated manner.

How is Acoustic CFD Analysis Performed? (Step by Step)

Geometry and Mesh Creation

  • 3D modeling of the area to be analyzed is created.
  • A mesh structure with appropriate resolution is determined for CFD.

Determination of Boundary Conditions

  • Sound source, flow velocity, turbulence models and wall conditions are defined.

Fluid Dynamics Simulation (CFD Run)

  • Turbulence and pressure changes of the flow are examined.
  • Data obtained from CFD calculations are prepared for acoustic analysis.

Acoustic Analysis

  • Sound propagation is calculated by solving acoustic equations.
  • Noise levels and sound wavelengths are analyzed.
  • Evaluation and Optimization of Results

Obtained data is interpreted and design changes are suggested to reduce noise.

Conclusion

Acoustic CFD analysis is a powerful tool for noise control and sound optimization in the field of engineering. Thanks to advanced simulation techniques, it is possible to determine sound sources, analyze their propagation and reduce noise. It plays a critical role especially in the fields of automotive, aviation and building acoustics.

As İntaç Engineering, we have successfully completed many CFD Analysis projects.