rigid_sphere_scattering
Computes exact far-field form function for rigid-sphere plane-wave scattering via Mie series, a closed-form reference to validate BEM acoustic scattering solvers.
Instructions
Exact rigid-sphere plane-wave scattering far-field form function via the Mie
series (NO solver) — the closed-form twin the Bempp exterior-acoustics BEM
scattering solve (acoustic_radiation_submit, problem='scattering') is gated
against. For compactness ka and scattering angle theta_deg (from the forward
direction; 180° is backscatter), f∞(θ) = (2/ika)·Σₙ(2n+1)[−j'ₙ(ka)/h'ₙ(ka)]·
Pₙ(cosθ) — a rigorous spherical-harmonic sum (Neumann ∂p/∂r=0 on the sphere)
truncated past convergence (fidelity='exact'). The backscatter |f∞(π)| → 1 in
the geometric (ka≫1) limit and rises through the resonance region. A BEM
scattered far field must land on |f∞(θ)|.
Returns {ka, theta_deg, a_m, form_function_abs, form_function_re, form_function_im, backscatter_abs, n_terms, fidelity, band_pct, valid_range_ok, warnings, escalate_to}.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| ka | Yes | ||
| a_m | No | ||
| theta_deg | No |