Highly Efficient Sound Radiation Calculation

AVL EXCITE™ Acoustics

AVL EXCITE™ Acoustics is a new tool of the EXCITE™ product family for the calculation of sound radiation in free field from vibrating structures such as engines and power units using the wave based technique (WBT).

AVL Approach

EXCITE™ Acoustics fits seamlessly into the EXCITE™ structural dynamic analysis workflow as the final step of acoustic analysis, using the FE mesh of the vibrating structure and the pre-calculated structural vibration (surface velocities) as input. That way it can also be used as a standalone tool as common FE formats are supported for the import of the vibrating structure geometry and the surface velocity boundary condition.

The WBT is based on an indirect Trefftz approach where by the dynamic acoustic pressure is expressed as a linear combination of wave functions, which exactly satisfies the homogenous Helmholtz equation. Since a fine acoustic mesh discretization is not required and is not dependent on the frequency, the wave based models are substantially smaller than acoustic models required for element-based methods like BEM or FEM. This enables accurate results to be achieved with high computational efficiency.

A unique automated procedure has been developed to generate the acoustic mesh starting from the unmodified structural FE mesh used for the structural vibration analysis. Thus the acoustic simulation model for the wave based analysis can be set up easy and very fast with a few mouse clicks.

Post-processing of airborne noise results such as sound pressure levels at microphone positions or on arbitrary field point meshes around the radiating structure is a separate and fast final step. This allows microphone positions and field point meshes to be added or modified without the need for recalculation of the sound radiation.

Benefits at a Glance

AVL EXCITE™ Acoustics efficiently supports the calculation of  sound radiation and derives airborne noise results which are directly comparable with measured acoustic data and legal noise limits.

Short analysis lead times from the start of modeling to result evaluation are facilitated with minimum effort for the model preparation due to an automated pre-processing tool for the generation of the acoustic mesh and wave based technique.

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