The development of scramjet engines is an important research area for advancing hypersonic and orbital flights. Progress toward optimal engine designs requires accurate flow simulations together with uncertainty quantification. However, performing uncertainty quantification for scramjet simulations is challenging due to the large number of uncertain parameters involved and the high computational cost of flow simulations. These difficulties are addressed in this paper by developing practical uncertainty quantification algorithms and computational methods, and deploying them in the current study to large-eddy simulations of a jet in crossflow inside a simplified HIFiRE Direct Connect Rig scramjet combustor. First, global sensitivity analysis is conducted to identify influential uncertain input parameters, which can help reduce the system’s stochastic dimension. Second, because models of different fidelity are used in the overall uncertainty quantification assessment, a framework for quantifying and propagating the uncertainty due to model error is presented. Finally, these methods are demonstrated on a nonreacting jet-in-crossflow test problem in a simplified scramjet geometry, with parameter space up to 24 dimensions, using static and dynamic treatments of the turbulence subgrid model, and with two-dimensional and three-dimensional geometries.
The development of scramjet engines is an important research area for advancing hypersonic and orbital flights. Progress toward optimal engine designs requires accurate flow simulations together with uncertainty quantification. However, performing uncertainty quantification for scramjet simulations is challenging due to the large number of uncertainparameters involvedandthe high computational costofflow simulations. These difficulties are addressedin this paper by developing practical uncertainty quantification algorithms and computational methods, and deploying themin the current studyto large-eddy simulations ofajet incrossflow inside a simplified HIFiRE Direct Connect Rig scramjet combustor. First, global sensitivity analysis is conducted to identify influential uncertain input parameters, which can help reduce the system's stochastic dimension. Second, because models of different fidelity are used in the overall uncertainty quantification assessment, a framework for quantifying and propagating the uncertainty due to model error is presented. These methods are demonstrated on a nonreacting jet-in-crossflow test problem in a simplified scramjet geometry, with parameter space up to 24 dimensions, using static and dynamic treatments of the turbulence subgrid model, and with two-dimensional and three-dimensional geometries.
The purpose of this document is to define the rules of governance for the Sandia Postdoctoral Development (SPD) Association. This includes election procedures for filling vacancies on the SPD board, an all-purpose voting procedure, and definitions for the roles and responsibilities of each SPD board member. The voting procedures can also be used to amend the by-laws, as well as to create, dissolve, or consolidate vacant SPD board positions.
The SNL SPD Association represents all personnel that are classified as Postdoctoral Appointees at Sandia National Laboratories. The purpose of the SNL SPD Association is to address the needs and concerns of Postdoctoral Appointees within Sandia National Laboratories.
This paper presents recent results from a set of large eddy simulations (LES) related to the Hypersonic International Flight Research Experiment (HIFiRE). The focus of these calculations is on the ground based experiments performed in the HIFiRE Direct Connect Rig (HDCR). Through matching the geometry and conditions of the HDCR experiments, the goals of this work are to 1) investigate the turbulence and mixing characteristics of the high Reynolds flow with multi-species fuel injection, and 2) assess the resultant combustion regimes and finite-rate chemistry effects.