NASA/LaRC has a requirement for: Employ numerical simulations to investigate laminar-turbulent transition in a three-dimensional supersonic flow. Specifically, purchase services to enhance, apply, and transfer (non-commercial) transition simulation capability developed by Prof. Chaoqun Liu and Dr. Li Jiang from the Mathematics Department at the University of Texas at Arlington. This capability has been developed and exercised under AFOSR Research Grants F49620-01-1-0028, F49620-00-1-0220, F49620-99-1-0042, F49620-97-1-0033, F49620-95-1-0018, and F49620-96-1-0122, plus prior NASA Langley contracts NAS1-19016, NAS1-19312 under the small business innovative research (SBIR) program; and NASA Langley purchase requests RBC-1086, RBC-1193, and RBC-1209, which total to approximately $2.5 million.
1.1 BACKGROUND: The enhanced software will support the development of improved prediction techniques for laminar-turbulent transition in boundary-layer flows. The latter need is addressed under the Efficient Airframe Systems and Integration (EASI) program of the Aerospace Vehicle Systems and Technology Program Office via the subelement on Transition Physics and Modeling. Transition prediction is also an important element of the Supersonic Vehicle Technology program. Numerical database generated with the simulation code developed under this contract will provide detailed physical insights into the flow behavior during transition; suggest potential simplifications towards the development of engineering models for underlying flow phenomena, provide a posteriori verification for such models; or help design and interpret relevant experiments.
2.0 CONTRACTOR’S TASK REQUIREMENTS: This effort represents a follow on to prior work in which the contractor had developed a high-order, compressible, parallelized Navier-Stokes flow solver that is applicable to flows with shocks and applied it for simulations of linear and nonlinear instability wave propagation and roughness-induced receptivity phenomena in subsonic and supersonic boundary-layer flows. The accuracy of simulating the propagation of instability waves had been cross-validated for both two- and three-dimensional boundary-layer flows against predictions based on a reliable Parabolized Stability Equation (PSE) solver, NASA’s Langley Stability and Transition Analysis Code (LASTRAC). It is also expected that that the solver includes previously developed pre- and post-processing capabilities to facilitate easy interfacing with the LASTRAC code for the desired range of problems. The Contractor shall refine and exercise the above Navier-Stokes solver by performing the following additional tasks:
1. Implement/refine and evaluate a subgrid scale (SGS) model, preferably based on approximate defiltering of the resolved scales of motion, for large eddy simulation of a high-speed (M > 1) transitional/turbulent boundary layer. Perform direct and large eddy simulations of a canonical, two-dimensional boundary layer to provide detailed assessment of the accuracy and efficiency of the SGS model within transitional or turbulent regions of the flow field. The post-processing will include detailed information about first- and second-order single point statistics, as well as two-point correlations and/or frequency and wave-number spectra and kinetic energy budgets. To facilitate the extension of the simulation code to more realistic geometries, the contractor will also perform a preliminary investigation into suitable options to improve the efficiency of computing mean-flow solutions using the current solver.
The Contractor shall transfer the simulation capability (along with the results of the simulation) to NASA by providing necessary assistance to ensure that the code can be implemented and run on NASA’s Linux clusters. NASA will provide partial computational facilities towards this simulation by providing up to 5000 node cpu hours on an in-house PC cluster. The geometry of the configuration(s) will preferably model a configuration that has previously been used in an experiment/computation and/or represents a canonical flow field of wide interest.
2. As necessary, provide required technical assistance towards transition calculations to be carried out by researchers at NASA Langley Research Center. The Contractor will assist by providing a code(s) that is accurate and robust enough for a calculation pertaining to one or more stages of transition; provide guidance with appropriate use of the code; help set up the computational grid(s); as necessary, assist with troubleshooting during the simulation and with analyzing the data during and after the simulation (so as to provide useful physical insights towards the development and validation of lower fidelity models of the transition processes).
Option effort:
3. This task is similar to Task 1 above. If, under the base effort, the SGS model is found to be satisfactory for the simulation of transitional flows, then the contractor shall extend the large eddy simulations to crossflow induced transition in a three-dimensional boundary-layer flow. Otherwise, direct numerical simulations will be used to capture a significant portion of the transitional region. Again, the geometry of the selected configuration should model a flow geometry/conditions that has been (or is likely to be used) in an experiment or computation and/or represents a canonical flow. It is also desirable for the selected flow configuration to provide further insights into the feasibility/efficacy of one or more of the laminar flow control techniques of interest for next generation supersonic aircraft.
4. The contractor shall also provide required technical assistance to transfer the added simulation capability to NASA Langley Research Center as outlined in the context of tasks 1 and 2 above.
NASA/LaRC intends to purchase the items from the University of Texas at Arlington. NASA LaRC has pioneered a number of innovations in transition simulation during the early nineties. Due to a steady decline in funding during late nineties, however, much of this capability has eroded not only at LaRC, but over U.S. as a whole. In this respect, Prof. Liu and Dr. Jiang’s research has been rather unique in terms of having remained active in transition simulation research throughout these years, having demonstrated the capability to simulate the different stages of boundary-layer transition process over both simple and airfoil geometries as well as across a wide range of speeds (incompressible, subsonic and supersonic) and, finally, having developed simulation code(s) that are amenable to efficient execution in a parallel environment. There exist one or two other research groups that have a similar capability in some respects. To the best of our knowledge, however, they do not possess a comprehensive, demonstrated capability for three-dimensional flows with crossflow instabilities; shock capturing in supersonic flows; and, most importantly, established accuracy against and crosstalk with NASA’s LASTRAC code. This functionality, which is essential for the tasks outlined in the statement of work, has been described in recent publications and reports by Prof. Liu, Dr. Jiang and their collaborators. Thus, we believe that only University of Texas would be in a position to meet the stated requirements, especially within the limited duration of the period of performance (twelve months from contract turn-on). The Authority for Other Than Full and Open Competition is 6.302-1.
The Government does not intend to acquire a commercial item using FAR Part 12. See Note 26.
Interested organizations may submit their capabilities and qualifications to perform the effort in writing to the identified point of contact not later than 4:30 p.m. local time on June 14, 2004. Such capabilities/qualifications will be evaluated solely for the purpose of determining whether or not to conduct this procurement on a competitive basis. A determination by the Government not to compete this proposed effort on a full and open competition basis, based upon responses to this notice, is solely within the discretion of the government.
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All responsible sources may submit an offer which shall be considered by the agency.
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