Choosing a solver
Start with the least costly method that supports both your physics and your desired output. The table lists supported combinations. All seven solver families return solution objects. Hover a column header for what that solver is. Hover the ℹ️ icon next to a geometry for its caveats, or follow a linked geometry name to the page covering it.
| Boundary condition | Modal | T-matrix | Kirchhoff | FEM | BEM | MFS | Fourier |
|---|---|---|---|---|---|---|---|
| Rigid |
Sphere Spheroid Cylinder ℹ️ |
Sphere Spheroid Cylinder ℹ️ Arbitrary ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ Arbitrary ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ |
Sphere Spheroid Irregular ℹ️ |
|
| Locally reacting (impedance) | Sphere ℹ️ | Sphere ℹ️ | |||||
| Pressure-release |
Sphere Spheroid Cylinder ℹ️ |
Sphere Spheroid Cylinder ℹ️ Arbitrary ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ Arbitrary ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ |
Sphere Spheroid Irregular ℹ️ |
|
| Fluid or gas interior |
Sphere Spheroid Cylinder ℹ️ |
Sphere Spheroid Cylinder ℹ️ Arbitrary ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ Arbitrary ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ |
Sphere Spheroid Irregular ℹ️ |
|
| Solid elastic |
Sphere Cylinder ℹ️ |
Spheroid ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ |
||||
| Elastic shell, fluid interior |
Sphere Cylinder ℹ️ |
Spheroid ℹ️ |
Sphere ℹ️ Spheroid ℹ️ Cylinder ℹ️ |
||||
| Elastic shell, empty interior | Spheroid ℹ️ |
Sphere ℹ️ Spheroid ℹ️ |
|||||
| Fluid shell, fluid or vacuum interior | Sphere | Sphere ℹ️ | Sphere ℹ️ | Sphere ℹ️ | |||
| Viscoelastic layered shell, fluid interior | Sphere ℹ️ | ||||||
| Coupled fluid regions, nested or disjoint | Sphere ℹ️ |
Sphere ℹ️ Spheroid ℹ️ |
Arbitrary ℹ️ | ||||
| Planar free surface or seafloor |
Sphere ℹ️ Spheroid ℹ️ |
Choosing by question
- Use sphere or spheroid modal methods as analytical references, while checking series convergence and special-function conditioning.
- Use Kirchhoff to explore physical-optics behavior. A numerically converged surface integral does not establish validity of physical optics at low frequency.
- Use FEM or BEM when checking analytical reductions, geometry discretization, or interface coupling. Compare against a canonical case first. Full 3D volume FEM is the general-purpose reference for elastic and shelled spheres and spheroids.
- Use MFS when source placement is well controlled and its supported geometry suits the problem.
- Use BEM surface results for repeated observation-angle queries. Radial FEM spheres and cylinders provide complex backscatter; meridian FEM cylinders and spheroids also provide complex amplitudes at arbitrary bistatic angles.
- Use Fourier matching for a smooth irregular body of revolution between the canonical (sphere/spheroid) and general numerical (BEM/MFS/FEM) solvers. See Fourier matching.
See BEM and MFS for the underlying boundary integral and source-fitting theory.