Objective

Businesses must develop multi-physics, component-based reduced-order models and associated interfaces to accelerate high-fidelity design tools for predicting detailed, time-accurate hypersonic vehicle flow-fields.

Description

The Army wants to design the next-generation hypersonic flight vehicles with enhanced system speed, reach and lethality to address the Army’s and Department of Defense’s priorities in Long Range Precision Fires and Hypersonics. The revolutionary systems must meet new tactical requirements for performance, reach and lethality.

Computational fluid dynamics play a central role in the design and development of hypersonic vehicles. This is due to prohibitive costs associated with testing facilities. However, existing CFD approaches have prohibitive computational costs when attempting to predict high Reynolds number hypersonic aerothermodynamics and their interactions with fully resolved physical processes.

Hypersonic modeling under realistic flight conditions is complicated by the present nonlinearity and multiphysics nature that acts across a wide range of scales. Variations in atmospheric conditions, chemical kinetics, vibrational excitation, ablation products and gas-surface interactions further complicate high enthalpy flow and plasma.

Recent detailed direct molecular simulations have also demonstrated macroscopic impacts of complex transport phenomena often omitted in coarse grained models such as Large Eddy Simulation and Reynolds Averaged Navier Stokes. The computational expense associated with solving complex coupled fluid, thermal, kinetic and structural problems currently limits the rate of accurately exploring a design space.

Recent successes accelerating the modeling of complex flows of similar computational complexity through component-based ROMs suggest the potential for model acceleration strategies that exploit coupling of local, mesoscale ROM domains. Newly developed localized ROM domain partitioning, nonlinear compression and adaptivity suggest the potential to attain greater efficiency and scalability than state-of-the-art models through the mitigation of high Kolmogorov n-width complexity associated with device-scale, transient turbulent flows.

The vendor must integrate the technology with associated multiphysics couplings to shorten the design cycles of revolutionary capabilities that accelerate high-fidelity, external and internal aerothermodynamics. The Army seeks scalable, adaptive model-order reduction technologies capable of recovering high-fidelity predictive power for the flight environment of a hypersonic vehicle, associated gas-flow chemistry, detailed transport, shock induced heating and their associated material responses.

The Army wants to achieve at least an order-of-magnitude reduction in computational cost versus existing wall-resolved LES techniques. It also wants to recover full Direct Numerical Simulation accuracy levels on transitional flows where wall-modeled results diverge from WR-LES and DNS solutions. While the Army will not consider non-invasive, data-driven model order reductions or fully invasive ROM technologies, it will prioritize approaches that develop modular compressed bidirectional data interfaces that enable tight coupling among diverse physics tools with improved scalability.

The new tools should handle realistic glide body, missile geometries and scramjet propulsion systems for sustained powered flight in the Mach 6 to 20 range. The Army encourages models that reduce sensitivity to near-wall mesh quality. Tools must have the ability to deploy in traditional/emerging high-performance computing architectures and demonstrate efficient weak scaling that is at least competitive with LES models. The Army also encourages the development of compressed interfaces for in-situ visualization and data-extraction techniques enabling seamless navigation of the sea of data encountered in real-time analysis.

Phase I

Vendors must develop component-based reduced order model (ROM) technologies that, once trained, demonstrate accurate 3D high-fidelity prediction of transient hypersonic boundary layer flows that can transition to novel flow conditions within training set bounds.

The technology must attain an order-of-magnitude reduction in memory footprint compared with existing state-of-art WR-LES of commensurate accuracy without explicitly defined wall models. It should offer the ability to recover DNS level solution accuracy in geometries incompatible with existing wall models should with order-of-magnitude speedup relative to state-of-the-art, fully-resolved high-order DNS solutions.

The vendor must demonstrate performance scaling for high-fidelity, reacting turbulence commensurate with finite rate chemical kinetics– based DNS solutions. It must also demonstrate detailed transport. The company should identify the strengths and weaknesses associated with alternative solutions, methods and new concepts. Businesses must demonstrate the theoretical credibility of proposed computational methods.

The Army will conduct computational vetting and demonstration of concepts using canonical, blunt-nose single or double cone hypersonic shapes and simple flameholder geometries at the minimal Reynolds number required to demonstrate transitional flow behaviors is suitable in this phase. The Army encourages solutions capable of maintaining order-of-magnitude speedups with ROM training or adaptation time included without loss of predictive accuracy across parametrically varying geometric configurations.

Phase II

During Phase-II, the vendor will extend and validate the framework developed in Phase-I to support the hypersonic design of potential applications in air-breathing missiles, boost-glide missiles and high-maneuver interceptors. Tools should demonstrate the ability to model complex aerothermochemistry, transport, thermoacoustics, shock induced heating and structural material responses with statistical properties shown to converge towards DNS and canonical experimental data. The computational cost should be at least one order of magnitude below WR-LES models for equivalent conditions.

The vendor should have a fluid-structure component-based ROM coupling that enables conjugate heat transfer and fluid structure interaction calculations to accurately model sharp features resulting from shock-heating. The tools must inherit the ability to capture in detail non-equilibrium processes, including boundary layer transition to turbulence, onset of material ablation, finite-rate non-equilibrium chemistry and the gas-surface interactions responsible for surface deformation from baseline full-order DNS models.

The business must demonstrate the tight coupling of time-accurate predictions through compressed component-based ROM interfaces for fluid structure interactions, parametric variations of both flow boundary conditions, design properties and external hypersonic vehicle flows. The Army expects complete model, multi-physics ROM interface application programming interfaces and executable code for deployment on state-of-the-art high performance computing systems with demonstrable performance on existing or emerging computing.

Teams must demonstrate model validation by comparison with experiments, reference DNS databases in the open literature or data from the Army or DoD laboratories. The Army emphasizes capturing turbulent transition at dramatically reduced computational complexity for arbitrary geometries and flow conditions. The complete software package shall be available to ARL during all phases of the project to conduct an independent assessment of the developed tools.

Businesses will coordinate with the government and potential prime-contractor partners to ensure product relevance and compatibility with missile defense projects, government modeling and simulation systems. While the Army does not require compatibility with specific production codes, selection will favor projects with viable transition strategies for either enhancing or supplanting production codes in existing, high-cost multiphysics analysis pipelines. The business shall deliver developed computational tool sets, along with user guides at the end of Phase-II, to the Army Research Laboratory for government use on HPC platforms and mission projects.

Phase III

This work will enable collaboration with high-fidelity simulation model developers and/or users on the integration of products into accelerated missile defense application pipelines. The long-term optimization of toolsets and APIs to accommodate new advances in the technology of tracking and prediction of glide body or cruise missile flight will continue. The technology will transition to an appropriate government or defense contractor for integration and testing. The integration and validation into design cycles for a real-world missile defense application will also continue.

Submission Information

All eligible businesses must submit proposals by noon ET.

To view full solicitation details, click here.

For more information, and to submit your full proposal package, visit the DSIP Portal.

STTR Help Desk: usarmy.rtp.devcom-arl.mbx.sttr-pmo@army.mil