I also put on this page some Asymptote codes to generates 3D schemes of waveguides and plates.
➤  First, we use an optimised warping to separate each modal component
➤  Then, we recover the dispersion curves with an optimised maximum method
➤  Finally, we implement a penalized minimization algorithm to recover the location of the source
➤  Using finite elements, PML's and
a post-processing to handle backward modes
➤  Using a 3D Lamb-SH modal decomposition computed using 2D-convolutions
Wavefield in a 2D acoustic waveguide at locally resonant frequencies. In red, we represent the locally resonant coordinate.
Black: initial shape defect. Red: reconstruction of the shape defect slightly shifted for comparisons.
➤  Using finite elements and PML's
➤  Using a modal decomposition with modified Airy functions computed using 1D-convolutions
Initial inhomogeneity in a 2D waveguide
Reconstruction using the multifrequency scattering method
➤  Data for the forward problem are generated using finite elements and PML's
➤  The inversion is performed using a penalized Tikhonov least square algorithm
Scheme of a 3D waveguide with a shape defect