Uncertainty Quantification for High-Speed Store Separation
This presentation will focus on an existing Frontier Project titled “Uncertainty Quantification for Hypersonic Vehicle Development”.  We have two primary technical goals for this project. First, we seek to demonstrate the application and utility of a well-established uncertainty framework for propulsion and aerodynamics problems relevant to a hypersonic strike platform. Second, we aim to explore methods to reduce the resource requirements of the process to enable the routine application of UQ practices outside the construct of a Frontier Project.

This Frontier Project is executing targeted simulations that contribute to the prediction of aerodynamic and propulsion performance of a hypersonic strike platform. The UQ framework we will follow is known as a probability bounds analysis. We will discuss how we identified sources of uncertainty, categorized them, and built a metamodel from hybrid RANS/LES CFD simulation data, which was then used to propagate the simulation uncertainties to map their impact on performance metrics.  The resulting cumulative distribution functions will establish how the relevant performance metrics respond to uncertainties in the simulation input parameters, enabling project managers to make risk informed decisions throughout the design and development process.

This presentation will focus on the aerodynamics studies from the Frontier Project, specifically the separation of a notional high-speed weapon from a generic weapon bay. For a store released at hypersonic speeds, the sensitivities of the trajectory to input parameters are currently unknown and unquantified.  This lack of understanding drives experimental and computational campaigns to cover a wider portion of the flight envelope than may be strictly necessary to capture the first-order effects of store motion.  The uncertainty studies for the store separation cases will be based on ground test campaigns conducted at the CUBRC LENS II facility in Buffalo, NY as part of the AFRL/RQH Pony Express program.  The test data includes full-scale trajectory data resulting from a separation event at hypersonic conditions.  The UGM presentation will detail the results of a sensitivity study and results to date for uncertainties in store trajectory.
IMPACT
The DoD impact of our proposed Frontier Project will be the demonstration of a UQ framework that enables risk informed decisions throughout the design and development process of a reusable hypersonic strike vehicle. The inclusion of data that establishes the confidence in simulation predictions will be critical to program leaders tasked with making decisions based on simulation data given the severe ground test limitations within our existing T&E infrastructure for testing hypersonic vehicles at this scale.
PRESENTER
Eymann, Timothy
timothy.eymann@us.af.mil
937-656-4885
AFRL/RQHV
CATEGORY
Comp Fluid Dynamics
SECONDARY CATEGORY
Mod, Sim & Analysis for Decision Making
SYSTEM(S) USED
Raider, Carpenter, Narwhal