I also put on this page some Asymptote codes to generates 3D schemes of waveguides and plates.
![](images/spectro.png)
 ➤  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
![](images/disp.png)
![](images/plaque1.png)
 ➤  Using finite elements, PML's and
a post-processing to handle backward modes
 ➤  Using a 3D Lamb-SH modal decomposition computed using 2D-convolutions
![](images/guide2.png)
Wavefield in a 2D acoustic waveguide at locally resonant frequencies. In red, we represent the locally resonant coordinate.
![](images/guide2rec.png)
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
![](images/inhomog1.png)
Initial inhomogeneity in a 2D waveguide
![](images/inhomog2.png)
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
![](images/pipe3D.png)
Scheme of a 3D waveguide with a shape defect