Flow Simulations for Acoustic Applications
Numerical flow simulation in the field of aeroacoustics contribute a lot in early development phases to design a low-noise product. This helps with saving time and money.
Acoutic calculations deal with the sound formation, sound optimiziation and sound prevention.
The output of the simulation is the sound pressure level response on a desired receptor point. That signal is afterwards analyzed concering sound pressure level and frequencies. Through that the most important noise sources of the application can be identified and in consequence be optimized or prevented. If necessary it is possible to do on-site measurements and to evaluate them in combination with the simulations.
bionic surface technologies has years of experience in different fields of application.
Possible Simulation Methods
Noise generation through inflows, boundary layers, vortex shedding
Main occurence in fans, rotors, barriers, channels, sound absorbers, clefts
Noise generation through vibrations or stimulations with natural frequencies and their multiples
- Underwater Acoustics
Noise generation through hydrodynamic stimulation
Possible Calculation Methods
Resolution of the acoustic pressure variation directly in the CFD simulation
Acoustic sources are taken from the CFD simulation
Analytic calculations of the sound propagation from the source to a desired reception point
Acoustic Simulations for Turbomachines
Scope for Simulations
- Wind power plants
Application: Simulation of a low-pressure turbine stage
- Analysis of the noise emissions in the turbine
- Resolution of the acoustic pressure variations
- Examinations of the blade repetition rate and the broad band noise
- Calculations with FW-H – acoustic analogy
Acoustic Simulations for Vehicles
Scope for Simulations
- Attachments like antenna, wing mirror, windshield wiper, roof girder, sun roof
- Air conditioning and fans
- Side window booming
- Outlet noises
- Interior acoustics
- Engine flow
- Total vehicle simulation
Applications: Simulation of the engine flow
- Analysis of the noise sources in the engine flow
- Total vehicle simulations
- Calculation with CAA – direct acoustic
Acoustic Simulations for Lawn Mowers
- Aeroacoustic analysis of the sound emitters and their optimization
- Comparison of the measurements and development of a vitual blade and case test bench
The acoustic calculation is carried out with the calculation method FW-H acoustic analogy. The acoustic sources were taken from the CFD simulation and analytic calculations were carried out of the sound propagation from the source to the desired reception point (see scheme on the right side).