Advanced Computational Tools for Jet Interaction Phenomena
Summary:
Tetra Research Corporation (Huntsville, AL) partnered with Pointwise, Inc., Intelligent Light, and SGI Federal to develop a computational fluid dynamics (CFD) program called Tetrex that solves high-speed flow problems. In 1998, BMDO awarded Tetra a Phase II SBIR to develop jet interaction (JI) control analysis software. Currently, Tetra is applying the software to missile defense projects. The company just completed calculating JI control, analyzing basic aerodynamic information, and gathering data on airflow surrounding missiles for the Theater High Altitude Area Defense (THAAD) system. Tetrex can be configured to work on low-density, low-speed flow problems such as chemical vapor deposition and spray combustion modeling as well.
Technology Description:
Tetra developed Tetrex, a CFD program, to solve high-speed flow problems easily and efficiently. Tetrex accurately calculates JI control, which is used to maneuver and stabilize missiles that have no fins. There are many factors that affect JI control, such as the placement of the jets on the missile, the missile=s altitude, and the chemistry of the combustible gas used to fire the jets. Tetrex is an all-inclusive package that will handle geometry, turbulence, and chemistry data in a single code.
The jets take the roles of tail and wing to control the kill vehicle. JI consists of two phenomena that influence the missile, they are the thrust of the jet and the change in surface pressure over the missile. The amount of control obtained from each jet should be determined before the missile launch. Each jet manipulates the missile in a different way. For instance, firing a side jet produces a lateral force. The flow of air coming over the missile will interact with the hot gas streaming out the side jet and create a wraparound effect, influencing the surface pressure. The variation in surface pressure will, in turn, affect the forces acting on the missile. Calculations gained from Tetrex will determine the size of the jet needed, placement of it on the missile, and where in the atmosphere the missile should be operated.
The force of the jets on the missile will be competing with the force of the atmosphere. Higher density air found at lower altitudes will be more likely to interact with the jet, whereas at higher altitudes, rarified air will interact less leaving the jets as the single force acting on the missile. Tetrex can compute the effects of jet interaction from ground level up to altitudes of 65 km; beyond that there is not much need for JI control analysis.
The type of combustible gas used to fire the jet is also a factor. Tetrex software offers a comprehensive analysis of jet interaction by accounting for the chemical, heat transfer, and thermodynamic processes taking place in addition to merely analyzing the effects of fluid flow.
Tetrex software was designed to be simpler than conventional programs, which require the user to be an expert in CFD calculations. The user of Tetrex software would need a background in aerospace engineering to input the data, but would not have to be an expert in CFD to run the program. Tetrex=s primary differentiating feature is an unstructured grid, which allows for greater flexibility, ease of use, and generality. The grid encompasses a variety of volumetric elements, including hexahedra, tetrahedra, prisms, and pyramids.
MDA Origins:
In 1998, BMDO awarded Tetra a Phase II SBIR to develop jet interaction controls. Jet interaction controls will help develop faster, lighter, more maneuverable, and more accurate defense interceptor systems and achieve highly effective control authority across large portions of the battlespace.
Spinoff Applications:
Tetrex can be used for evaluating high-speed flow problems related to missile defense. The software can also be modified to solve low-density, low-speed flow problems for commercial applications such as chemical vapor deposition and spray combustion.
Commercialization:
Tetra partnered with three commercial companies to improve its CFD software. Pointwise, Inc., worked with Tetra to formulate the Tetrex pre-processor portion, which automatically forms the computational grid. Intelligent Light developed the post-processor, which allows easy data analysis by interfacing with the visualization program. SGI Federal teamed with Tetra to make the software more compatible with the computer hardware.
Currently, Tetra is using Tetrex for government projects related to missile defense.
THAAD Missile Program: Tetra has recently completed working flow issues of the THAAD system, which is being developed to intercept short- and medium- range ballistic missiles inside and outside Earth=s atmosphere. The company used its Tetrex software to compute JI and calculate basic aerodynamics as well as gather data from airflow surrounding certain areas of the missile.
Compact Kinetic Energy Missile Program: The Compact Kinetic Energy Missile (CKEM) is a new initiative being undertaken by the U.S. Army for incorporation into the Future Combat System (FCS). The FCS is a combination of manned and unmanned vehicles that will operate interdependently on multiple platforms. CKEM is planned to be a smaller, lighter version of the Army=s Line-of-Sight Anti-Tank Missile. CKEM is still in its early stages; Tetra is looking into using Tetrex for high-speed flow applications in the CKEM program.
Low Cost Interceptor Program: The U.S. Army=s Low Cost Interceptor (LCI) initiative intends to demonstrate that a long-range, low-cost missile interceptor system can be developed using current capabilities and existing components. LCI will be designed to complement existing missile systems. The interceptor will be designed to target fixed-wing aircraft, helicopters, unmanned aerial vehicles, etc., as well as cruise missiles. Tetra is looking into a possible application for Tetrex in the LCI program.
Company Profile:
Tetra specializes in CFD research, development, and applications for a variety of engineering disciplines. Tetra currently has partnerships with Pointwise, Inc., Intelligent Light, and SGI Federal.
Contact Information:
Dr. Rex Chamberlain
Principal Research Scientist
Tetra Research Corporation
Huntsville, AL
Phone/Fax: 256-539-1075
email: rex@tetraresearch.com
web: www.tetraresearch.com
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