Comment on " Triggering of Longitudinal Combustion Instabilities in Rocket Motors: Nonlinear Combustion Response"

Triggering of oscillations in rocket motors is the subject of an ongoing investigation at the California Institute of Technology. Some issues that have been previously addressed in several recent publications by the authors [1-3] have more recently been examined by Wicker et al.[4] Whereas the latter paper provides a thorough investigation of the equations as derived, it apparently overlooks the possible effects of two key approximations that were used in the derivation of these equations. Some of the possible effects of these assumptions have been addressed previously, [3] and the authors suggest that the work by Wicker et al. might have benefited from our earlier and accessible conclusions.