Examples of radiation resistance and radiation mass
At low frequencies, two approximated expressions of resistances and radiation mass are often used:
Radiation resistance | Radiation mass | Length correction | |
In a screen |
|
|
|
In the end of a tube |
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|
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Radiation mass is sometimes assimilated to that of a cylinder of fluid with same cross-section as the piston / guide, and then expressed as the length of this cylinder ("length correction").
Remarque : Remark
At low frequencies
so
The value of a radiation resistance
remains small compared to the radiation reactance
. The load effect on an acoustic source can thus be approximated by
.
