Streamlining the Development of Next-Generation Launch Vehicles
As NASA embarks on an ambitious new path to develop a next-generation launch system more swiftly and economically, cutting-edge analysis tools will be critical to streamlining the design process while also ensuring the highest possible performance and safety standards. With the Space Shuttle due to retire next year, a new launch system capable of carrying large payloads into orbit will be essential to continuing NASA's science and exploration missions.
Modeling and simulation experts in the NASA Advanced Supercomputing (NAS) Division at NASA Ames Research Center are performing advanced aerodynamic simulations that supply critical design performance data more quickly and inexpensively than ever before. NASA-developed computational fluid dynamics (CFD) codes are used to model new launch vehicle designs and compute the detailed aerodynamic flows, forces, and interactions that could affect flight performance and safety during launch.
"CFD analyses help fine-tune the design process by enabling early optimization of vehicle aerodynamics, and rapid assessment of potential changes or new details," said Cetin Kiris, chief of the NAS Applied Modeling and Simulation Branch. "This leads to better initial designs and more efficient design analysis cycles."
Gauge pressure contours are shown on the Ares V vehicle and surrounding structures, and exhaust gases are depicted by an isocontour at 5% concentration. Note that acoustic pressure waves radiate predominantly in the direction of the flame trench. (Jeffrey Housman, NASA/Ames)
Over the past year, NAS CFD experts have provided pivotal support for development of the Ares V Heavy Lift Launch Vehicle (HLLV) by delivering extensive "aerodynamic databases" of forces and loads throughout the launch trajectory. Their results have supplemented limited wind tunnel data, and have enabled more conditions and designs to be assessed-all at a fraction of the cost and time that would have been required for obtaining data through testing alone.
New computational tools and techniques have also been developed to simulate the HLLV's launch conditions, which will be even more intense than those generated by the Space Shuttle's 7 million pounds of thrust. These analyses predict critical pressure loads and acoustic noise levels during ignition and liftoff to assess the suitability of existing launch facilities for larger vehicles and to ensure that excessive vibrations won't damage their valuable payloads.
In addition, NAS CFD experts have performed high-fidelity simulations of stage separation for the Ares I launch vehicle. These simulations give unique insight into the complex aerodynamic effects and plume interactions that play an important role in determining whether the first stage booster separates cleanly from the upper stage engine. Because plume effects from separation motors cannot be tested in wind tunnels, these simulation capabilities will be crucial to designing safe separation systems for future launchers.
The launch vehicle simulation advances achieved through these projects, combined with NASA's world-class supercomputing resources, have poised NAS CFD teams to provide cutting-edge design analysis for the next phases in the launch vehicles' development. Use of increasingly powerful computing resources and higher-fidelity CFD models will give designers ready access to more valuable performance data, and allow them to consider complex design factors with greater accuracy than ever before.
More information:
+ CFD Support for Heavy Lift Launch Vehicles (PDF-131 KB)+ Launch Environment Simulations (PDF-197 KB)
+ Aerodynamics of the Ares I Crew Launch Vehicle During Stage Separation (PDF-209 KB)
Contact information:
Cetin C. Kiris
Chief, Applied Modeling & Simulation Branch
NASA Advanced Supercomputing (NAS) Division, NASA Ames Research Center
cetin.c.kiris@nasa.gov
(650) 604-4485
