Hypersonic Aerothermodynamics, High-Speed Propulsion and Materials
Hypersonic flight provides an unprecedented capability by simultaneously extending range and reducing transit time—enabling rapid reach and global targeting. High performance hypersonic offensive and defensive weapons require efficient aerodynamic designs with light-weight, durable control surfaces and leading edges capable of sustaining the extreme exposure during flight across a wide range of conditions. The Hypersonic Aerodynamics, Heat Transfer and Materials program aims to advance technologies enabling hypersonic and high-speed weapons as well as scientific knowledge for candidate Navy hypersonic systems such as the hypervelocity projectile (HVP), boost-glide weapons and air-breathing tactical missiles. Improvements in computational models and measurement techniques enable more aggressive designs that enhance lethality, survivability and range. Validated predictive multidisciplinary design tools that confidently reduce the allowable design margins enable high performance hypersonic and high-speed weapons.
Research Concentration Areas
The near sea-level launch of low-drag guided projectiles at hypersonic speeds poses unique aerothermal and material challenges. The computation and ground testing of such flows are demanding due to the large free-stream unit Reynolds numbers in excess of 100 million per meter. For projectiles, understanding the interplay between multiple competing boundary-layer transition mechanisms such as transient growth, entropy-layer instabilities, 1st mode, 2nd mode, and crossflow as a function of the flight conditions and surface finish remain an unsolved problem. Boost glide weapons also involve complex flow physics due to the high flight enthalpies and wide range of operating conditions experienced during reentry, pull-up, glide, and terminal dive. The ability to predict the state of the boundary layer over the vehicle, including the control surfaces, is crucial to reducing design margins. High-speed, air-breathing propulsion technology, such as solid fuel ramjet (SFRJ) propulsion, offers the potential to significantly increase the range of tactical missiles within naval size constraints.
Research Challenges and Opportunities
- Boundary layer transition prediction methods applicable to complex geometries that incorporate (1) receptivity to free-stream disturbances, particulates and roughness, (2) linear growth, and (3) non-linear breakdown for multiple competing mechanisms. This also includes the validation against high quality experimental data.
- Novel flow control strategies for (1) extending regions of laminar flow, and (2) for avoiding excessive flow separation and reducing peak heating loads on control surfaces. Such strategies require modeling and ground tests to increase the technology readiness level (TRL) prior to flight demonstrations.
- Experiments and computations to improve the understanding of boundary layer physics in shock-wave dominated flows around slender geometries with highly swept fins.
- Reduced order models to predict surface heat transfer rates and fluctuating pressure distributions in hypersonic turbulent and transitional boundary layers and shock-wave/boundary-layer interactions. The models need to incorporate residual effects from specific laminar-turbulent breakdown mechanisms.
- Novel methodologies to develop improved RANS and LES wall models from high fidelity computations (DNS) and/or detailed measurements.
- Novel flow diagnostics for non-intrusive, time-resolved measurements of velocity and thermodynamic state-variables that can be successfully transitioned from small-scale hypersonic facilities to large-scale test and evaluation (T&E) facilities such as shock tunnels, expansion tunnels, blowdown tunnels, Ludwieg tubes, and arcjets.
- Physics-based, fully-coupled computational tools to predict environment-material interactions such as surface-chemistry, in-depth material response, and weather and atmospheric particles effects on hypersonic weapons. The tools should be validated through novel diagnostics, facilities, and experimental data.
- Computational models for aero-thermo-servo-elastic effects arising from control surface actuation at high speed. The models should be validated though novel experimental techniques.
- High-fidelity computational tools to predict surface pyrolysis, flame-holding limits, coupled turbulence / finite-rate chemical kinetics and radiative heat transfer effects for SFRJs operating over a wide range of conditions.
- Experimental studies with advanced diagnostics under relevant conditions to improve the understanding of critical phenomena for SFRJ combustion such as solid fuel pyrolysis and recession, fuel mixing and flame-holding limits.
- New methodologies for the integration, design and test of air-breathing, missile tactical inlets with operability over a wide range of altitudes, velocities and angles of attack.
- New methodologies to increase the efficiency and throttleability of SFRJs.
- Advanced ultra-high temperature materials, cooling strategies, and thermal protection systems.
Program Contact Information
How to Submit
Submit white papers, QUAD charts and full proposals for contracts to this email address: ONR Code 35 Research Submissions
Follow instructions within BAA for submission of grant proposals to grants.gov website.