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## The effect of flow on transverse oscillations of two parallel magnetic tubes

We study oscillations of two parallel interacting magnetic tubes in the presence of plasma flow along the tubes. Using the cold plasma and thin tube approximations we derive the system of two equations describing these oscillations. This system of equations is valid for equilibria where the plasma density and flow velocity can vary along the tube axes and in time. This system of equations is used to study the effect of flow in the tubes on the frequency of standing waves. There are two modes of oscillations, fast and slow. We calculated the dependence of frequencies of fast and slow modes of the Alfv ´en Mach number. We found that the effect of flow in coronal loops on the oscillation frequency is fairly weak for typical flow velocities observed in coronal loops. Ho we ver it can be substantial in the case of prominence threads. We discuss the implication of the obtained results on coronal seismology