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Elastic cylinder modal series (ECMS) solution

Source: R/model-ecms.R
ECMS.Rd

Computes backscatter from straight and uniformly bent finite elastic cylinders by combining the phase-shift solution for an infinite elastic cylinder with the finite-length coherence factor used for normal and near-normal incidence, plus the Fresnel coherence correction used for uniformly bent cylinders. In the current package class system, the elastic cylinder is carried most naturally by an ESS-class cylinder within the broader elastic-based ELA family, with the elastic-cylinder properties stored on the shell slot. Legacy FLS-class cylinders are also accepted as geometry carriers for backward compatibility.

Usage

This model is accessed via:


target_strength(
  ...,
  model = "ECMS",
  sound_speed_sw,
  density_sw,
  density_body,
  sound_speed_longitudinal_body,
  sound_speed_transversal_body,
  m_limit
)

Arguments

sound_speed_sw

Seawater sound speed (\(m~s^{-1}\)).

density_sw

Seawater density (\(kg~m^{-3}\)).

density_body

Elastic-cylinder density (\(kg~m^{-3}\)). If omitted, the model uses the density stored on the scatterer body.

sound_speed_longitudinal_body

Longitudinal wave speed in the elastic cylinder (\(m~s^{-1}\)).

sound_speed_transversal_body

Transversal (shear) wave speed in the elastic cylinder (\(m~s^{-1}\)).

m_limit

Optional model truncation limit used to cap the number of retained cylindrical modes.

References

Faran, J.J. (1951). Sound scattering by solid cylinders and spheres. The Journal of the Acoustical Society of America, 23: 405-418.

Stanton, T.K. (1988). Sound scattering by cylinders of finite length. II. Elastic cylinders. The Journal of the Acoustical Society of America, 83: 64-67.

Stanton, T.K. (1989). Sound scattering by cylinders of finite length. III. Deformed cylinders. The Journal of the Acoustical Society of America, 86: 691-705.

Gorska, N., Ona, E., and Korneliussen, R. (2005). Acoustic backscattering by Atlantic mackerel as being representative of fish that lack a swimbladder. Backscattering by individual fish. ICES Journal of Marine Science, 62: 984-995.