### Abstract

Near-field acoustical holography (NAH) is a well-established method to study acoustic radiation near a stationary sound source in a homogeneous, stationary medium. However, the current theory of NAH is not applicable to moving sound sources, such as automobiles and trains. In this paper, the inclusion of a moving medium (i.e., moving source and receiver) is introduced in the wave equation and a new set of equations for plannar NAH is developed. Equations are developed for the acoustic pressure, particle velocity, and intensity when mean flow is either parallel or perpendicular to the hologram plane. If the source and the measurement plane are moving at the same speed, the frequency Doppler effect is absent, but a wave number Doppler effect exists. This leads to errors when reconstructing the acoustic field both towards and away from the source using static NAH. To investigate these errors, a point source is studied analytically using planar NAH with flow in one direction. The effect of the medium moving parallel to the hologram plane is noted by a shift of the radiation circle in wave number space (k-space). A k-space Green's function and a k-space filter are developed that include the effects of the moving medium.

Original language | English (US) |
---|---|

Pages (from-to) | 420-429 |

Number of pages | 10 |

Journal | Journal of the Acoustical Society of America |

Volume | 112 |

Issue number | 2 |

DOIs | |

State | Published - Aug 19 2002 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Arts and Humanities (miscellaneous)
- Acoustics and Ultrasonics

### Cite this

*Journal of the Acoustical Society of America*,

*112*(2), 420-429. https://doi.org/10.1121/1.1477931

}

*Journal of the Acoustical Society of America*, vol. 112, no. 2, pp. 420-429. https://doi.org/10.1121/1.1477931

**Planar near-field acoustical holography in a moving mediuma.** / Ruhala, Richard J.; Swanson, David Carl.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Planar near-field acoustical holography in a moving mediuma

AU - Ruhala, Richard J.

AU - Swanson, David Carl

PY - 2002/8/19

Y1 - 2002/8/19

N2 - Near-field acoustical holography (NAH) is a well-established method to study acoustic radiation near a stationary sound source in a homogeneous, stationary medium. However, the current theory of NAH is not applicable to moving sound sources, such as automobiles and trains. In this paper, the inclusion of a moving medium (i.e., moving source and receiver) is introduced in the wave equation and a new set of equations for plannar NAH is developed. Equations are developed for the acoustic pressure, particle velocity, and intensity when mean flow is either parallel or perpendicular to the hologram plane. If the source and the measurement plane are moving at the same speed, the frequency Doppler effect is absent, but a wave number Doppler effect exists. This leads to errors when reconstructing the acoustic field both towards and away from the source using static NAH. To investigate these errors, a point source is studied analytically using planar NAH with flow in one direction. The effect of the medium moving parallel to the hologram plane is noted by a shift of the radiation circle in wave number space (k-space). A k-space Green's function and a k-space filter are developed that include the effects of the moving medium.

AB - Near-field acoustical holography (NAH) is a well-established method to study acoustic radiation near a stationary sound source in a homogeneous, stationary medium. However, the current theory of NAH is not applicable to moving sound sources, such as automobiles and trains. In this paper, the inclusion of a moving medium (i.e., moving source and receiver) is introduced in the wave equation and a new set of equations for plannar NAH is developed. Equations are developed for the acoustic pressure, particle velocity, and intensity when mean flow is either parallel or perpendicular to the hologram plane. If the source and the measurement plane are moving at the same speed, the frequency Doppler effect is absent, but a wave number Doppler effect exists. This leads to errors when reconstructing the acoustic field both towards and away from the source using static NAH. To investigate these errors, a point source is studied analytically using planar NAH with flow in one direction. The effect of the medium moving parallel to the hologram plane is noted by a shift of the radiation circle in wave number space (k-space). A k-space Green's function and a k-space filter are developed that include the effects of the moving medium.

UR - http://www.scopus.com/inward/record.url?scp=0036333276&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036333276&partnerID=8YFLogxK

U2 - 10.1121/1.1477931

DO - 10.1121/1.1477931

M3 - Article

VL - 112

SP - 420

EP - 429

JO - Journal of the Acoustical Society of America

JF - Journal of the Acoustical Society of America

SN - 0001-4966

IS - 2

ER -