Hypersonics Center on its way toward being a national leader

Since its opening in 2004, the Hypersonics Research Center at the University of Minnesota has developed into one of the leading academic programs in hypersonics research. Center researchers are developing advanced simulation methods to support the design of future hypersonic aircraft and planetary entry spacecraft. These methods are being validated in the nation’s premiere hypersonic test facility located at CUBRC Inc. The Center is supported by the Air Force Office of Scientific Research (AFOSR), Sandia National Laboratories, and NASA. During the past year, there have been a number of significant research accomplishments at the Center.
A critical issue in hypersonic vehicle design is predicting transition to turbulence. Center researchers, lead by Dr. Heath Johnson, have been developing a set of computational methods to predict the growth of instabilities and their breakdown to turbulence in hypersonic flows. Extensive work is being conducted to validate this tool. In recent work, we have used this code to predict the location of transition to turbulence on a blunted cone at Mach 7 and 10 conditions. Comparisons with the CUBRC wind tunnel measurements are very encouraging, with the simulations predicting transition much more accurately than widely used empirical correlations. The results of this study are being used to design a sounding rocket flight experiment as part of the joint U.S. – Australia HIFiRE (Hypersonic International Flight Research Experimentation) program. This set of transition prediction codes is being used at national laboratories, universities, and in the aerospace industry for the analysis of hypersonic aircraft and spacecraft.
Center researchers have been working on the design of inward-turning hypersonic inlets for scramjet engines for the past several years. Recently, Travis Drayna, a graduate research assistant at the Center, has developed the capability to optimize the performance of these inlets. He uses a third-party multidisciplinary design optimization tool and the advanced flow field simulation methods developed at the Center to iteratively compute the optimal inlet shape. This approach has lead to improved inlet designs, and more importantly, it has illustrated how the flow physics can be manipulated to improve inlet performance. This approach will be applied to a number of optimization problems, including the design of a new inlet for a wind tunnel being developed at CUBRC.
Center graduate student research assistants David Peterson, Pramod Subbareddy, and Ryuta Suzuki have been developing advanced approaches for simulating injection and mixing inside scramjet engines. This approach resolves the key large-scale turbulent motion, resulting in a more accurate representation of the turbulent mixing process. A critical aspect of this work is the development of high-quality numerical methods to reduce the artificial dissipation in the simulations. The interaction between shock waves, turbulence, and turbulent combustion is the focus of Center graduate student researchers, Yucheng Hou and Jeff Doom. They, and Center postdoctoral researcher, Dr. Noma Park, have developed highly accurate simulation methods and unsteady turbulence models, that will be applied to scramjet flows.
During the past six months, there has been an interesting off-shoot from the hypersonic aerodynamics work being done at the Center. The Mars Science Laboratory (MSL) will be launched in 2009, and will land a large rover on the surface of Mars. This will require the use of a very large parachute that will open at high altitude and supersonic speed. The Jet Propulsion Laboratory is concerned that the parachute will be unstable and will not produce the required drag. Center researchers, along with AEM Prof. William Garrard, are developing methods to predict the parachute dynamics including the interaction of the capsule wake with the canopy.

Graham Candler
Krishnan Mahesh