Eigenfrequency Study

In the eigenfrequency formulation, the source terms are absent, and the eigenmodes and eigenfrequencies are solved for:

(11-6)

The eigenvalue λ introduced in this equation is related to the eigenfrequency f and the angular frequency ω, through λ = i2πf = iω. Because they are independent of the pressure, the solver ignores any dipole and monopole sources unless a coupled eigenvalue problem is being solved.

Equation 11-6 applies to the 3D case. The equations solved in eigenfrequency studies in lower dimensions and for axisymmetric geometries are obtained from their time-harmonic counterparts, given in the previous subsection, by the substitution ω2→−λ2.

Switch between specifying the eigenvalues, the eigenfrequencies, or the angular frequencies by selecting from the Eigenvalue transformation list in the solver sequence’s Settings window for Eigenvalue.