Missile Aero-Acoustic Response Modeling

Large dynamic pressure loads occur on missile airframes produced by aerodynamic interactions associated with lateral/divert jet firings and from varied separation events (stage, shroud, submunitions dispense). The accurate prediction of such loads is acritical element of missile design since mission failures have been directly related to vibration problems (e.g. guidance component failure) stemming from such interactions. No first-principles-based simulation methodology is available to support design,and present engineering methods have proven to be inadequate. The Phase I effort initiates the path towards development of an advanced modeling framework. Key elements include:(1)the formulation of a hybrid LES/RANS CFD framework to predict rigid bodydynamic pressure loads associated with divert jet firing interactions;(2)the validation of this framework using new PIV data with detailed turbulent statistics;(3)the inclusion of rudimentary structural response capabilities into the CFD code which willprimarily attenuate the dynamic loads on the missile surface.An optional task is proposed to investigate the dynamic loads on a seeker window associated with the shroud separation event. The partially open shroud has resonant characteristics of a forwardfacing cavity and there are very strong bow shock oscillations and resultant large dynamic loads on the seeker window.There are no existing high-fidelity techniques to predict hypersonic flow structural aero-acoustic response associated with eventsproducing surface vibrations. In addition to providing major benefits to the entire missile community, this research has direct applicability to the design of reusable launch vehicles and to space planes which must perform multiple missions and thus havemore stringent structural requirements. It is also directly applicable to the design of missile launchers and to scramjet combustors where plume/fuel jet aerodynamic interactions produce large dynamic pressure loads. Discussions with NASA and primecontractors have indicated significant commercial potential for this modeling to support space/launch vehicle design.