The operator model for flow of viscouse fluid between two coaxial cilinders is considered. Asymptotic of spectrum is obtained. Eigenfunctions of corresponding linear pencil form Bari basis in special Hilbert space. The operator model for flow of non-viscouse fluid between two coaxial cilinders is considered. The structure of spectrum is investigated. There are an interval of essential spectrum. The problem of accumulation of eigenvalues to bounds of essential spectrum is studied.
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