Meshing for Acoustics BEM analysis

In a Simcenter 3D Acoustics BEM analysis, you use a mesh of 2D elements to define only the boundary surface of the acoustic fluid. The mesh requirements for BEM acoustic analyses depend on whether you are using the direct or indirect approach.

BEM acoustic analysis type	Application	Mesh requirements
Direct BEM acoustic analysis	Exterior sound radiation	The 2D mesh must be closed and manifold. Additionally, the elements' normals must be consistent and correctly aligned so that they point outward from the part.
Indirect BEM acoustic and vibro-acoustic analysis	Interior and exterior sound radiation	The 2D mesh can be open or closed and manifold or non-manifold.

Meshing for direct BEM analyses

Step	Substep	Details	Related help topic
1. Simplify outer skin of the structural mesh.	a. If the structural mesh is a 3D mesh, create a 2D mesh from the 3D mesh.	Use the Surface Coat command to create a 2D skin mesh from the existing 3D structural mesh.	Surface coat of 2D elements
b. Defeature the 2D mesh.	Use commands, such as Remove Rib, to remove features from your model.	Rib detection and removal within a mesh
c. Remove holes from the 2D mesh.	Use the Mesh from Boundary command to fill holes in the 2D mesh with elements and create a closed mesh.	Creating a mesh inside an existing boundary
2. Create the 2D mesh that defines the boundary surface of the acoustic fluid.		Use the Surface Wrap Recipe command with the Wrap Around the Exterior and the 2D Mesh Only options to create a 2D mesh that wraps around the entire exterior of the structural mesh.	Surface Wrap RecipeSurface coat of 2D elements
3. Validate the mesh.	a. Ensure that all element normals have a consistent direction.	Use the 2D Element Normals command to check the orientation and alignment of the element normals. Use the Orient Normals by Seed Element option to correct the orientation of any inconsistent normals so that they all point outward from the part.	Checking and orienting the normals of 2D elements
b. Verify that the 2D mesh is closed and manifold.	Use the Element Edges command to verify that the mesh does not contain any free or non-manifold edges.	Checking for free and non-manifold element edges
4. Create the microphone mesh to output acoustic results at those locations.		Create a microphone mesh in the appropriate shape and location.	Using microphone mesh to capture analysis results

Meshing for indirect BEM analyses

Step	Substep	Details	Related help topic
1. Simplify outer skin of the structural mesh.	a. If the structural mesh is a 3D mesh, create a 2D mesh from the 3D mesh.	Use the Surface Coat command to create a 2D skin mesh from the existing 3D structural mesh.	Surface Wrap RecipeSurface coat of 2D elements
b. Defeature the 2D mesh.	Use commands, such as Remove Rib, to remove features from your model that are not significant to the frequency range of the analysis.	Rib detection and removal within a mesh
c. Remove holes from the 2D mesh that are not relevant for the acoustic analysis.	Use the Mesh from Boundary command to fill holes in the 2D mesh with elements.	Creating a mesh inside an existing boundary
2. Create the 2D mesh that defines the boundary surface of the acoustic fluid.		Use the Surface Wrap Recipe command with the Wrap Around the Exterior and the 2D Mesh Only options to create a 2D mesh that wraps around the entire exterior of the structural mesh.	Surface Wrap RecipeSurface coat of 2D elements
3. Validate the mesh.	a. Ensure that all element normals have a consistent direction.	Use the 2D Element Normals command to check the orientation and alignment of the element normals. Use the Orient Normals by Seed Element option to correct the orientation of any inconsistent normals so that they all point in the same direction.	Checking and orienting the normals of 2D elements
b. Verify the location of any non-manifold or free edges.	Use the Element Edges command to highlight the location of any non-manifold or free edges.	Checking for free and non-manifold element edges
4. Create the microphone mesh to output acoustic results at those locations.		Use the appropriate mesh or primitive mesh command to create the microphone mesh.	Using microphone mesh to capture analysis results

Learn more

Meshing for acoustic analyses

Supported element types for Acoustics BEM analysis

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Fluid materials for acoustic analyses

Supported fluid material properties

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Meshing for Acoustics BEM analysis, Simcenter 3D 2021.1 Series

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