Orlov

A problem of fluid oscillations in tanks of space launch vehicles is quite well known and has been investigated extensively during the last decades. This is caused by the fact that the major mass of a liquid-propellant rocket is fluid and its forced motion affects vehicle controllability significantly. In their recent works the authors considered small oscillations in tanks with a propellant intake and with fuel reallocation inside a vehicle. Such problems have arisen due to the purpose of increasing efficiency and output performance of multistage cluster rockets by central stage fueling from side stages of a cluster. The problem of propellant free oscillations in cylindrical and conical tanks was considered, and solutions were presented with boundary conditions on a free surface and the surface of intake that, figuratively speaking, provides resistance to the fluid descent. Eigen-frequencies and Eigen-values of perturbed motion equations with dissipation on boundary surfaces were found. It was shown that slow fluid decent and intake surface boundary conditions may affect both oscillating and damped terms of the solution.