Linear acoustic gains and losses in solid propellant rocket motors

1 he general significance of acoustic gains and losses to the problem of rocket motor stability is discussed briefly Recently, considerable progress has been made toward the understanding of some of the important loss mechanisms These are noted and attention is called to their significance With respect to acoustic gains, the burning surface of the propellant is recognized to be a principal source of acoustic amplification, and a considerable amount of experimental and theoretical attention has been devoted to the determination of the propellant response function It is recognized that, in view of the highly complicated nature of the phenomena, one should hardly expect quantitative agreement between theory and experiment Nevertheless, one should be entitled to expect agreement of a qualitative natui e whenever the suppositions of the theory are reasonably well met by the conditions of experiment A comparison of the kinds of results obtained suggests that such a qualitative similarity does not always exist, particularly for low burning rates As a result, it seems likely that some mechanism, which can be important under these conditions, has been omitted from consideration in the existent theoretical model Theoretical calculations, as yet unpublished, indicate that under some conditons radiation may exert an important influence on the acoustic response of the burning surface, especially at low burning rates (Radiative effects have been omitted in previous theoretical treatments ) The general nature of the new calculations and some of the numerical results are discussed c = C = Cp = / = j = k = m = n = P = go = T =