Elmer was applied to the simulation of a simple accelerometer in the absense and presense of large perforation holes. The purpose of the holes is to supress the squeezed-film effect occuring in the small cavities. The computational mesh was constructud with Netgen.

The computation was done utilizing the harmonic elasticity and Reynolds equations. The effect of the squuzed-film to the eigenmode was not taken into account. Thus, the Reynolds equation was computed after the eigenmode had been resolved. The eigenmode computation was boosted by defining the mass to be rigid which reduces the size of the matrix equation for the eigenmode computation.

The computational mesh consisted of around 44000 linear tets of which 75% belonged to the rigid body. The computational time required for the solution is in the order of a minute. Above are some snapshots of the simulation results for a case without and with perforation holes. The color corresponds to the fluidic pressure caused by the resonating movement. There are also animation of the case without holes, mpg, and with holes, mpg.