VMR083-CA1
VMR083-CA1
Sound Radiation of a Vibrating Sphere
Test Description
A sphere with radius R = 1 m is pulsating and radiating sound into an exterior unbounded field. At the surface of the sphere a normal velocity of vn = 0.1 m/s is prescribed.
| Geometric Properties | Material Properties | Loading | ||
|---|---|---|---|---|
| Sphere radius, R = 1 m |
| Normal velocity on the surface of sphere, vn = 0.1 m/s |
Results
The frequency spectrum of the sound pressure level value is calculated at the surface of the sphere (r = 1 m) and a distance of r = 15 m from the center of the sphere. The results are compared with the analytical solutions for frequencies 20, 40, 60, 80, and 100 Hz with the frequency range of excitation from 0 to 100 Hz and at 200, 300, 400, and 500 Hz for frequency range of excitation from 100 to 500 Hz. Analytical values of pressure are calculated by:
Analytical values of sound pressure level in dB are calculated by:
where
| pref = the reference pressure (2 x 10-5 N/m2 by default) |
 = root mean square of peak pressure in the modal and harmonic
analysis |
------------- r=1m, 0-100Hz ---------------
| Freq(Hz) | MECHANICAL APDL | RATIO |
0.200000E+02 0.11416E+03 1.0000
0.400000E+02 0.11884E+03 1.0000
0.600000E+02 0.12078E+03 1.0000
0.800000E+02 0.12173E+03 1.0000
0.100000E+03 0.12225E+03 1.0000
-------------- r=15m, 0-100Hz -------------
| Freq(Hz) | MECHANICAL APDL | RATIO |
0.200000E+02 0.90631E+02 0.9999
0.400000E+02 0.95316E+02 0.9999
0.600000E+02 0.97252E+02 1.0000
0.800000E+02 0.98203E+02 1.0000
0.100000E+03 0.98726E+02 1.0000
--------------- r=1m, 100-500Hz ------------
| Freq(Hz) | MECHANICAL APDL | RATIO |
0.200000E+03 0.12305E+03 1.0000
0.300000E+03 0.12322E+03 1.0000
0.400000E+03 0.12328E+03 1.0000
0.500000E+03 0.12331E+03 1.0000
-------------- r=15m, 100-500Hz ------------
| Freq(Hz) | MECHANICAL APDL | RATIO |
0.200000E+03 0.99551E+02 1.0002
0.300000E+03 0.99703E+02 1.0000
0.400000E+03 0.99798E+02 1.0004
0.500000E+03 0.99932E+02 1.0014