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dc.contributor.authorMoshman, Nathan D.
dc.contributor.authorSritharan, Sivaguru S.
dc.contributor.authorHobson, Garth V.
dc.date.accessioned2015-04-15T18:14:46Z
dc.date.available2015-04-15T18:14:46Z
dc.date.issued2011
dc.identifier.citationInternational Journal of Flow Control, Volume 3, Number 4, 2011en_US
dc.identifier.urihttp://hdl.handle.net/10945/44960
dc.description.abstractThis paper presents the first solution of an optimal control problem concerning unsteady blast wave attenuation where the control takes the form of the initial distribution of liquid water droplets. An appropriate two-phase flow model is adopted for compressible homogeneous two-phase flows. The dynamical system includes an empirical model for water droplet vaporization, the dominant mechanism for attenuating the jump in pressure across the shock front. At the end of the simulation interval, an appropriate target state is defined such that the jump in pressure of the target state is less than that of the simulated blast wave. Given the nature of the non-linear system, the final time must also be a free variable. A novel control algorithm is presented which can satisfy all necessary conditions of the optimal system and avoid taking a variation at the shock front. The adjoint-based method is applied to NASA’s problem of Ignition Overpressure blast waves generated during ignition of solid grain rocket segments on launch vehicles. Results are shown for a range of blast waves that are plausible to see in the launch environment of the shuttle. Significant parameters of effective droplet distributions are identified.en_US
dc.rightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.en_US
dc.titleOptimal Control of Shock Wave Attenuation using Liquid Water Droplets with Application to Ignition Overpressure in Launch Vehiclesen_US
dc.typeArticleen_US
dc.description.funderN. D. Moshman would like to thank Professors Chris Brophy, Frank Giraldo and Wei Kang at the Naval Postgraduate School and Bruce Vu at NASA Kennedy Space Center. In addition, N. D. Moshman thanks the Naval Postgraduate School and the Army Research Office for funding this research.en_US


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