CAE Software【Femtet】Murata Software Co., Ltd.
Example4 Hemispherical Speaker
General
-
A hemispherical speaker is analyzed.
-
The distribution of sound pressure in the air is solved.
-
Unless specified in the list below, the default conditions will be applied.
Analysis Space
|
Item |
Settings |
|
Analysis Space |
3D |
|
Model unit |
mm |
Analysis Conditions
|
Item |
Settings |
|
Solvers |
Acoustic Analysis [Mach] |
|
Analysis Type |
Harmonic analysis |
|
Options |
N/A |
The harmonic analysis tab is set up as follows.
The sound waves propagate outside the analysis region. Therefore the “open boundary” condition below is applied initially.
|
Tab |
Setting Item |
Settings |
|
Harmonic analysis
|
Frequency |
Minimum: 1000[Hz] Maximum: 1000[Hz] |
|
Sweep Type |
Select “Log step” |
|
|
Sweep Setting |
Select Fast sweep. Tolerance: 1.0×10^-2 |
|
|
Open Boundary Tab |
Type |
Absorbing boundary |
|
Order of Absorbing Boundary |
1st degree |
|
|
Coordinates of Origin |
x = y = z = 0 |
Model
The air hemisphere is created from a solid body. The open boundary is set on the surface of the hemisphere.
A circular sheet body is defined for imprinting.
Its boundary condition type is speed.
Body Attributes and Materials
|
Body Number/Type |
Body Attribute Name |
Material Name |
|
0/Solid |
Air |
000_Air(*) |
* Available from the Material DB
The sound speed of air is set as follows.
|
Material Name |
Tab |
Settings |
|
000_Air(*) |
Sound Speed |
3.4×10^2[m/s] |
Boundary Conditions
The “speed” boundary condition is set on the face of the imprinting body.
|
Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Settings |
|
Open/Face |
Acoustic |
Open boundary |
|
|
VEL/Face |
Acoustic |
Speed |
1[m/s] |
Results
The gradation contour of the sound pressure at 100[Hz]
