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This paper compares the results and the computational efficiency of a research code with that of a commercial code on the same problem. The research code (REACT-MB) is tested using its unsteady hybrid large-eddy simulation/Reynolds-averaged Navier-Stokes (LES/RANS) method as well as a more common steady-state Menter RANS method. CFD++ of Metacomp is tested on the same problem using its realizable...
Despite efforts to maintain streamlined shapes for minimal resistance and noise, US Navy marine vehicles oftentimes must have bluff body geometries or must operate in off-design modes. These situations produce separated flows that are unsteady. At large scales the flow unsteadiness may be the cause of structural concerns while the entire range of fluid dynamic scales, from large to small, may be the...
Flow separation from lifting surfaces such as airfoils is undesirable as it deteriorates performance. For example, when airfoils that are designed for large Reynolds numbers are operated at smaller off-design Reynolds numbers, laminar separation can occur. Laminar separation typically leads to transition and reattachment. Transition is influenced by factors, such as free-stream turbulence and wall...
The Weather Research and Forecasting (WRF) model has been used extensively in research and operational theaters on a broad range of computer architectures. There is a need for a standard suite of case studies by which to benchmark a computational platform's potential to efficiently support WRF and, concurrently, a need to push WRF into increasingly larger problem sizes in order to test the capability...
The Hawaiian Islands consist of dramatic terrain changes over short distances, resulting in a variety of microclimates in close proximity. To handle these challenging conditions, weather models must be run at very fine vertical and horizontal resolutions to produce accurate forecasts. Computational demands require Weather Research and Forecasting (WRF) to be executed in parallel on the Maui High Performance...
This paper reports on radio frequency (RF) sources that have been virtually-prototyped with the Improved Concurrent Electromagnetic Particle-in-Cell (ICEPIC) code. ICEPIC simulates from first-principles, Maxwell's equations and Lorenz's force law, the electrodynamics and charged particle dynamics of the RF-producing part of the system. Our simulations focus on several proposed variants of the L-band...
Modeling of complex systems typically requires many iterations of theoretical design, numerical simulation, and analysis. The goal of this project was to develop an automated optimization framework to optimize a 0.22 THz traveling wave tube (TWT) high-power amplifier design. Applications for such an amplifier include three-dimensional (3D) imaging systems for medical uses, detection of concealed hazardous...
Machine affinity is the observed phenomena that some applications benefit more than others from features of high performance computing (HPC) architectures. When considering a diverse portfolio of HPC machines manufactured by different vendors and of different ages, such as the set of all supercomputers currently operated by the Department of Defense High Performance Computing Modernization Program,...
High performance reconfigurable computers (HPRCs), which combine general-purpose processors (GPPs) and field programmable gate arrays (FPGAs), are now commercially available. These interesting architectures allow for the creation of reconfigurable processors. HPRCs have already been used to accelerate integer and fixed-point applications. However, extensive parallelism and deeply pipelined floating-point...
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