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Benchmark Problem A0-4F

-Properties-
category
type
index
domain
object
note
A. exterior
0. basic
A0-4F
frequency
sphere
scattering

Geometry:
Spherical surface (1 m in diameter) in the free field.

Boundary condition:
The surface is rigid boundary. A piston source (0.2 m in diameter) (S) is located on the surface of the sphere, assuming its stationary vibration with acceleration amplitude 1.0 m/s2.
Fig. A0-4F-1: Geometry of problem A0-4F (unit: m).
-Task A-

Directivity:
Sound pressure amplitude [Pa] at 181 points (R1), 2 m away from the sphere's center on the plane x = 0, located at 1 deg intervals (theta = 0, ..., 180 deg). At the octave-band mid-frequencies (f = 31.5, 63, 125, 250, 500, 1k, 2k, 4k Hz).

Dataform:
d-a0-4fa.xls

Contribution:
  • [03/10/15] A0-4FA-01:Multipole expansion, Oshima, T.
-Task B-

Frequency response:
Sound pressure amplitude [Pa] of a total field (the sum of an incident field and a scattered field) at 3 points (0, 0, 1) (R2), (0, 1, 0) (R3) and (0, 0, 10) (R4). At the frequencies with 1 Hz intervals from 20 Hz to 4 kHz; or with 50 Hz intervals from 50 Hz to 4 kHz.

Dataform:
d-a0-4fb.xls

Contribution:
  • [04/05/18] A0-4FB-01:Multipole expansion, Oshima, T.