Effect of Wave Propagation in Feed Lines on Low-Frequency Rocket Instability

A s imple rocket s y s t e m has been analyzed for low-frequency instabil i ty, taking into account the compressibil ity of the fluid in the propellant l ines . A numerical example has been given. The example i l lustrates tha t the effect of compressibility m a y become important for practical cases. It shows also tha t l engthening of the l ines m a y not always be beneficial and that , for a given t i m e lag, the frequency of operation m a y no t change greatly wi th l ine l ength .