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FCMS

Source: vignettes/fcms/index.Rmd
index.Rmd

Overview

Benchmarked Validated
Theory Implementation

The finite-cylinder modal-series solution (FCMS) calculates monostatic scattering from a straight circular cylinder near broadside.

Core idea

Solve the circular cross-section in cylindrical partial waves, then apply the finite-length coherence factor that describes addition along the straight cylinder axis (Stanton 1988, 1989).

Best for

  • Straight, constant-radius finite cylinders near broadside
  • Comparing fixed-rigid, pressure-release, liquid-filled, and gas-filled cylinder boundaries
  • Canonical cylinder benchmarks before adopting an asymptotic model

Supports

  • Cylinder shapes carried by FLS or GAS scatterers
  • Homogeneous fluid or gas interiors, plus fixed-rigid and pressure-release limits
  • Monostatic complex amplitude, backscattering cross-section, and target strength

Main assumptions

  • A straight centerline and circular, constant-radius cross-section
  • Broadside or near-broadside incidence
  • Finite length represented by a coherence factor
  • No elastic shear response in the cylinder interior

Validation status

  • Benchmarked against the canonical finite-cylinder spectra stored in benchmark_ts.
  • Validated against the echoSMs finite-cylinder implementation.

Family pages

  • Implementation: cylinder construction, boundaries, output, and comparisons
  • Theory: cylindrical modes, interface conditions, and finite-length closure

References

Stanton, T. K. 1988. “Sound Scattering by Cylinders of Finite Length. I. Fluid Cylinders.” The Journal of the Acoustical Society of America 83 (1): 55–63. https://doi.org/10.1121/1.396184.
Stanton, T. K. 1989. “Sound Scattering by Cylinders of Finite Length. III. Deformed Cylinders.” The Journal of the Acoustical Society of America 86 (2): 691–705. https://doi.org/10.1121/1.398193.