Building, maintaining and deploying software is a complicated and risky proposition in the best case scenario. Successfully achieving this within a government organization, specifically The Department of Defense (DoD), is rare. Computational Research Engineering and Analysis Tools and Environments (CREATE), the software development arm of the HPCMP, is a unique example of a DoD software development success story. This paper documents the history of the HPCMP CREATE(TM) program since its inception in 2006, some reasons for its success, challenges it has overcome, and the importance of its longevity. Documenting this history provides a unique window into the minds of the originators and the confluence of ideas and hardware that made it possible.

NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract Thermodynamic Considerations in Determining World Carrying Capacity Abstract Applying knowledge of thermodynamic systems and laws (laws of mass, energy and entropy) to the overall the earth system and to individual human systems, leads to the concept of a minimum-sized control volume (called “transition control volume”). Such a control volume is the minimal control volume that is theoretically needed to cycle all mass, energy and entropy flows required by the open system of an individual human. Such processes and fluxes are necessary for an individual human to exist without environmental limitations on life. Using simplified assumptions of just two out of many necessary components, energy fluxes, the carbon cycle, and heat rejection, this thermodynamic model analysis is used to estimate the human carrying capacity of the earth with current non-renewable energy usage. If all the earth’s inhabitants were to use non-renewable energy at the same rate as the average Unite States citizen, the carrying capacity of the world would be about 770 million people. If the average energy consumption is limited to around 40 gigajoules per year (1200 watts) and is derived primarily from renewable energy sources and if natural background heat flux from the core of the earth is supplemented by 5%, the carrying capacity is estimated to be 3.8 billion. These estimates are based on using very simplified assumptions and limited input data (like using just three fluxes mentioned above) for performing the calculations using the thermodynamic model proposed. The model, however, is capable of more accurate and comprehensive calculations and predictions, if the quality and extent of input data is improved. Observations of problems related to energy sources and sinks in human societies show more chronic sink-related problems than source-related problems. To think that energy sink-related problems can be solved by the increased use of supplemental, non-renewable energy is erroneous. If the entropy and temperature of the earth system are to remain at reasonably low level (natural level), the thermodynamic analysis presented in this paper, shows that use of supplemental non-renewable energy increases the entropy production, making the energy sink- related problems worse. Analyses of energy fluxes through the environment from this standpoint lead to the conclusion that the human carrying capacity is more likely limited by the transport of energy and entropy to single sink for the earth system and ultimately by the sink itself than it is by energy sources. Introduction Many authors have addressed the question of the human carrying capacity of the world, proposing various bases to estimate carrying capacity. Most rely on energy source or resource limitations, mainly food production, to establish maximums as illustrated by the following eight estimates1. 1. 5.994 Billion E. G. Ravenstein, 1891, food production limitations, 2. 15.634 Billion Albrecht Penck, 1924, food production limitations, 3. 146 Billion C. T. De Wit, 1967, non-agricultural land use limitations,

A good starting model is imperative in full-waveform inversion (FWI) because it solves a least-squares inversion problem using a local gradient-based optimization method. A suboptimal starting model can result in cycle skipping leading to poor convergence and incorrect estimation of subsurface properties. This problem is especially crucial for salt models because the strong velocity contrasts create substantial time shifts in the modeled seismogram. Incorrect estimation of salt bodies leads to velocity inaccuracies in the sediments because the least-squares gradient aims to reduce traveltime differences without considering the sharp velocity jump between sediments and salt. We have developed a technique to estimate velocity models containing salt bodies using a combination of global and local optimization techniques. To stabilize the global optimization algorithm and keep it computationally tractable, we reduce the number of model parameters by using sparse parameterization formulations. The sparse formulation represents sediments using a set of interfaces and velocities across them, whereas a set of ellipses represents the salt body. We use very fast simulated annealing (VFSA) to minimize the misfit between the observed and synthetic data and estimate an optimal model in the sparsely parameterized space. The VFSA inverted model is then used as a starting model in FWI in which the sediments and salt body are updated in the least-squares sense. We partition model updates into sediment and salt updates in which the sediments are updated like conventional FWI, whereas the shape of the salt is updated by taking the zero crossing of an evolving level set surface. Our algorithm is tested on two 2D synthetic salt models, namely, the Sigsbee 2A model and a modified SEG Advanced Modeling Program (SEAM) Phase I model while fixing the top of the salt. We determine the efficiency of the VFSA inversion and imaging improvements from the level set FWI approach and evaluate a few sources of uncertainty in the estimation of salt shapes.

This computational aerodynamics textbook is written at the undergraduate level, based on years of teaching focused on developing the engineering skills required to become an intelligent user of aerodynamic codes. This is done by taking advantage of CA codes that are now available and doing projects to learn the basic numerical and aerodynamic concepts required. This book includes a number of unique features to make studying computational aerodynamics more enjoyable. These include:The computer programs used in the book's projects are all open source and accessible to students and practicing engineers alike on the book's website, www.cambridge.org/aerodynamics. The site includes access to images, movies, programs, and moreThe computational aerodynamics concepts are given relevance by CA Concept Boxes integrated into the chapters to provide realistic asides to the conceptsReaders can see fluids in motion with the Flow Visualization Boxes carefully integrated into the text.

This computational aerodynamics textbook is written at the undergraduate level, based on years of teaching focused on developing the engineering skills required to become an intelligent user of aerodynamic codes. This is done by taking advantage of CA codes that are now available and doing projects to learn the basic numerical and aerodynamic concepts required. This book includes a number of unique features to make studying computational aerodynamics more enjoyable. These include:The computer programs used in the book's projects are all open source and accessible to students and practicing engineers alike on the book's website, www.cambridge.org/aerodynamics. The site includes access to images, movies, programs, and moreThe computational aerodynamics concepts are given relevance by CA Concept Boxes integrated into the chapters to provide realistic asides to the conceptsReaders can see fluids in motion with the Flow Visualization Boxes carefully integrated into the text.

Estimating a starting velocity model for Full Waveform Inversion can be challenging. It requires several passes of migration velocity analysis to obtain a model accurate enough to prevent cycle skipping. We present an alternative approach to estimate a 3D starting model using a global optimization method called Very Fast Simulated Annealing. To constrain the optimization problem with a large number of unknowns, we parameterize the 3D model with surfaces and velocities surrounding them and solve for the optimal parameters. The final estimated model from VFSA serves as a starting model for FWI. We demonstrate the effectiveness by comparing FWI results along a few 2D lines from the 3D model. The proposed method is largely automated and reduces numerous man hours required to build a starting model. We apply our proposed method to one toy model and one complex synthetic model. In both cases, we were able to obtain acceptable results. Use of VFSA with a sparse parameterization method makes our 3D global inversion a practical tool. Presentation Date: Tuesday, September 26, 2017 Start Time: 11:00 AM Location: Exhibit Hall C, E-P Station 3 Presentation Type: EPOSTER

The goal of the CREATE program is to develop and deploy physics-based computational engineering tools that can be used to develop virtual prototypes of ships, air vehicles, ground vehicles, and radio frequency antennas to accurately predict their performance in support of the US Department of Defense acquisition process, DoD 5000. The purpose of this article is to describe the approach taken to address the verification and validation of the CREATE software products. The approach is based on the adoption of a set of practices aligned with the recommendations of the National Academy of Sciences to promote a test-driven development culture.

The F-16XL flight vehicle has been used extensively to study the aerodynamics of medium- to high-angle-of-attack flight. Flight-test data, including surface pressures, are available for a wide range of flight conditions, allowing direct comparison between computational fluid dynamics and full-scale flight data. The most recent comprehensive study, made possible by NASA, was conducted by NATO Task Group AVT-113 and had participants from many different countries. One of the conclusions of the study was that unsteady flow simulations with high-resolution turbulence treatment was necessary to compare well with the high-angle-of-attack flight-test data. The current work applies the high performance computing CREATE (TM)-Air Vehicles Kestrel fixed-wing simulation tool to the F-16XL configuration at high-angle-of-attack flight conditions. Kestrel couples a near-body spatially second-order solver with an offbody, spatially third- or fifth-order solver to achieve a very high-resolution computation of the aerodynamic features of the flowfield. Adaptive mesh refinement is also performed in the offbody domain as the solution progresses to maintain the vortical structures away from the body. The resulting simulation data are compared to flight-test data, and they are found to be in very good agreement for this flight condition.

A synthesis is presented of recent numerical predictions for the F-16XL aircraft flowfields and aerodynamics. The computational analyses were all performed with hybrid Reynolds-averaged Navier–Stokes/large-eddy simulation formulations, with an emphasis on unsteady flows and associated aerodynamics, and results from five computational methods are included. The work focused on one particular low-speed high angle-of-attack flight-test condition, and comparisons against flight-test data are included. This work represents the third coordinated effort using the F-16XL aircraft, and a unique flight-test dataset, to advance the knowledge of slender airframe aerodynamics as well as the capability for predicting these aerodynamics with advanced computational fluid dynamics formulations. The prior efforts were identified as the Cranked-Arrow Wing Aerodynamics Project International.

In time-lapse (4D) seismic imaging, good survey repeatability is considered essential. However, there are cases where only poorly matched surveys have been acquired. In these scenarios, extracting useful 4D signal has to rely on favorable lithology (e.g., the presence of significant production-induced effects) and extra effort in 4D processing and imaging. This is precisely the task we have at hand to extract 4D signal from two completely different surveys: a baseline narrow-azimuth towed-streamer (NATS) survey and a monitor ocean-bottom seismic (OBS) node survey. Through careful 4D processing, we were able to extract clear and credible 4D signal related to reservoir changes. However, the background noise that is unrelated to reservoir changes (4D noise) remains high. We demonstrate a path to further reduce 4D noise through least-squares migration (LSM). By attempting to invert reflectivity from both baseline and monitor surveys separately, LSM implicitly minimizes both repeatable effects caused by overburden complexity (e.g., uneven illumination and migration artifacts given repeated acquisitions) and non-repeatable noise from acquisition differences and ambient noise. As expected, 4D differences extracted after LSM show a reduced noise level and improved signal fidelity that better correlates with production effects. We also tested the limits of LSM by removing a 4D binning step from the processing flow. However, this increased the 4D noise, indicating that 4D binning is still required for poorly repeated surveys. For 4D data with higher repeatability, it may be feasible to forgo 4D binning and rely solely on LSM to improve the similarity of the two surveys. Presentation Date: Tuesday, September 26, 2017 Start Time: 4:45 PM Location: 351F Presentation Type: ORAL

Large spectral differences exist between streamer and ocean bottom seismometer (OBS) data, mostly due to different surface-related ghost effects – streamer data have both shot- and receiver-side ghosts, while OBS data have only the shot-side ghost. In a recent OBS-streamer time lapse study in deepwater Gulf of Mexico, we investigated three schemes of spectral matching between OBS and streamer data: conventional 1D matching of streamer to OBS, receiver deghosting of streamer data only, and full deghosting of both data sets. The study demonstrated the benefits of receiver deghosting on streamer data over 1D matching, particularly because it provided a better match between the streamer and OBS data before migration and an increased 4D signal-to-noise ratio (S/N) after migration. However, we found that shot deghosting on both surveys did not improve the 4D results; instead, the spectra of streamer and OBS, especially at lower frequencies, were more different after shot deghosting. Receiver deghosting alone on the streamer data gave the best 4D results among the three schemes. Presentation Date: Tuesday, October 18, 2016 Start Time: 10:45:00 AM Location: 150 Presentation Type: ORAL