Protuberance Aerodynamic Loads for Space Launch Vehicle Systems Using Computational Fluid Dynamics

This paper present's the methodology used to determine the protuberance aerodynamic loads for NASA's Ares I Crew Launch Vehicle. The methodology presented used computational fluid dynamics to obtain pressures and forces on the protuberances. This is one of the first times computational fluid dynamics has been used to estimate protuberance aerodynamic loads for such a complicated configuration. The approach used a discrete matrix of computational fluid dynamics simulations and decomposed the protuberance in a manner suitable to give both the structural and venting engineers useful data. One of the guiding principles in the development of the data book was that the data book was to be used for analysis of protuberances and not in the design of the protuberance. In this regard, the data book contained significant conservatism both in the methodology and in the choice for a factor of conservatism. The methodology, along with advantages and disadvantages to the current approach, is discussed. Two examples of protuberances in the Ares I Aerodynamic Data Book are given.