1 Introduction
2 Green’s function and vibration of an inertial cluster
3 Homogenisation approximation
3.1 Spectral problem for an integral operator
3.2 Normalisation
3.3 Evaluation of the integral in (16)
4 Frequencies of the localised modes
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First, the normalised frequency parameter is determined by solving the equation corresponding to the imaginary term in (17):$$\begin{aligned} \mathrm {J}_{n}\left( \frac{{\tilde{\beta }}}{2}\right) = 0 \, . \end{aligned}$$(22)
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Then, given \({\tilde{\beta }}\), the ring radius R and the total mass M are derived from the equation$$\begin{aligned} \frac{{\tilde{\beta }}^{2}}{4}\mathrm {I}_{n}\left( \frac{{\tilde{\beta }}}{2}\right) \mathrm {K}_{n}\left( \frac{{\tilde{\beta }}}{2}\right) + 4 \pi \rho h \frac{R^{2}}{M} = 0 \, . \end{aligned}$$(23)