Abstract
General three dimensional dynamic equations of motion for a launch vehicle with varying mass are derived, having effects of airframe bending, propellant sloshing, propellant flow and engime swiveling into account. Further, assuming the propellant flow, lateral bending shapes and some small quantities concerning a vehicle, derived equations are applied to a moderate or large launch vehicle with multiple gimbaledengines, and the effects of aforementioned phenomena on tbe dynamic equations are shown in detail.
In this paper, the effect of propellant flow are considered as reaction forces of propellant to the airframe, and using the theory of continuum mechanics the time rate of change of integrals of some quantities are expressed by the net rate at which the quantities are being transfered out of the system.
