Sound Wave Mitigation Through the Design of Surface Impedance
Abstract
An artificial soft surface is proposed to reduce and attenuate the propagation of acoustic waves along the surface of hard ground. An infinitesimal pressure line source is used as the excitation. Instead of an ideal periodic structure, a quasi-periodic structure is used where a finite number of grooves are incorporated to model exactly the realistic situation. Two boundary integral equation methods are proposed, one is based on the free space Green's function. The multilevel fast multiple algorithm is used to speed up the matrix-vector product necessitated by iterative methods used in solving the final linear system. The second method is more efficient in that two half space Green's function are employed rather than the free space Green's function so that the edge effect is removed, which results from boundary truncation, and the size of the linear system is greatly reduced. They are then used to analyze the behavior of acoustic wave propagation above textured surfaces, the impedance of which is, as expected, altered. The effects of the number and the geometry of grooves, and the effect of source height are also investigated. The conclusions drawn can be used for reference in a practical problem of mitigating gun blast noise.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2005
- Accession Number
- ADA437068
Entities
People
- Gong L. Wang
- Weng C. Chew
Organizations
- University of Illinois Urbana–Champaign