Resonance Frequencies of a Room
This example studies the resonance frequencies of an empty room by using the Helmholtz equation for the time-harmonic pressure field Δp + k2p = 0 The resulting eigenmodes can be compared to and validated against the analytical solution for the resonance frequencies of a boxed enclosure, that is f = c/2*√( (i/lx)2 …
Two Material Wave Guide Interface
This example studies the interface between two different materials in a section of a wave guide. The change in material causes the waves to travel at different speeds. This changing diffraction pattern of the planar time harmonic waves can be investigated by using the Helmholtz equation for the amplitude of the waves A …
Vibration Modes of a Hollow Cylinder
This model studies the vibration modes of a free and hollow cylinder using an axisymmetric approximation. No loads or constrains are applied as the free modes are sought. The cylinder is 10 m long, has a center diameter of 2 m, and is 0.4 m thick. Moreover, the material of the cylinder is considered to be steel with E …
Vibrations of a Circular Membrane
This example computes the the vibration modes, eigenvalues, and frequencies for a circular drum or membrane. The membrane is modeled by the unit circle and assumed to be attached to a rigid frame. The Poisson PDE equation is used with the Eigenvalue solver to compute the solution. This model is available as an …
Interference and Diffraction
The classic double-slit experiment considers a planar and periodic oscillating wave which hits and passes two narrow slits. Assuming the slits are narrow enough, the passing waves will bend and cause an interference pattern, while diffraction will attenuate the off axis resulting amplitude. In the example the Helmholtz …