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Illustrating wave propagation phenomena

In this page, I am showing some numerical simulations that I completed, mainly during my thesis. These numerical experiments have been performed with the software Montjoie.

Didactic example for solving 2-D Helmholtz equation with finite element method

Demo Helmholtz The use of finite element methods is demonstrated for 2-D Helmholtz equation. The mesh and solution are generated with the pdetool package of Matlab. High-order curved elements are also experimented to show their efficiency.

Eigenvalues for domains presenting a singularity

Eigenvalue computation Benchmark for computing eigenvalues in domains that contain corners or singular edges. Nedelec's edge elements of the first kind are used in conjunction with hexahedral mesh with a local refinement.

Scattering by an aircraft at 750Mhz

Diffraction avion A plane wave is scattered by an aircraft. This time-domain simulation is performed with Discontinuous Galerkin method on hexahedral meshes, and with a local time-stepping strategy.

Scattering by an aircraft at 900Mhz

Diffraction avion The same experiment as the previous one is conducted for an higher frequency. It can be observed that the mesh seems a bit too coarse for this frequency.

Scattering by a satellite

Diffraction Genec A plane wave is scattered by a satellite (GENEC). The used local time stepping strategy is quite efficient on this case because of the presence of very small elements (thin slots, solar panels with a small thickness).

Resonance phenomena for a finite-length slot.

Diffrac Fente A wave is propagating through a finite-length slot. For some given frequencies, some resonances appear and the transmission coefficient is higher.

Propagation of a pulse through a slot

Diffrac Fente Propagation of a wave through a slot inside a wall. The time source is a Ricker.

Source point in a cobra cavity

Diffrac Cobra A wave is propagating inside a cobra cavity. The right side of the cavity is open (numerically a first-order absorbing boundary condition is set).

Random media in a waveguide

Diffrac guide Propagation of waves inside a waveguide, that is characterized by a media with slow random variations. The physical index random variation is less than 3%.

Random media in a big waveguide.

Diffrac guide This case is the same as the previous one, but for a larger waveguide (500 wavelegnths). The solution is represented by splitting the waveguide in several slices.

Benchmark of a selective optical filter

Benchmark Atmel Studying an optical band-pass filter. This filter is highly selective, and this sensitivity is favorable to high-order element methods.

Scattering of a plane wave by a thin wire

Diffrac Fil Electromagnetic waves are scattered by a thin wire. Several models are available (Holland's model, fictitious domain model)
Aero sphere Propagation of an acoustic wave in presence of a flow. Solving Linearized Euler equations with Discontinuous Galerkin method with hexahedral mesh.
Piano diffrac Propagation of an acoustic wave inside a piano-shaped cavity.
Lung diffrac Propagation of an acoustic wave inside the lungs.