22 Sep 2022

Ship Simulator of the Future in Virtual Reality

Introduction: The Army’s modernization priorities include the development of augmented reality and virtual reality (AR/VR) simulations for enabling the regiment and increasing soldier readiness. The use of AR/VR technology at the U.S. Army Engineer Research and Development Center (ERDC) is also growing in the realm of military and civil works program missions. The ERDC Coastal and Hydraulics Laboratory (CHL) has developed a ship simulator to evaluate bay channels across the world; however, the current simulator has little to no physical realism in nearshore coastal regions (Figure 1). Thus, the ERDC team is researching opportunities to advance ship simulation to deliver the Ship Simulator of the Future (SSoF). The SSoF will be equipped with a VR mode and will more accurately resolve nearshore wave phenomena by ingesting precalculated output from a Boussinesq-type wave model. This initial prototype of the SSoF application is intended for research and development purposes; however, the technologies employed will be applicable to other disciplines and project scopes, including the Synthetic Training Environment (STE) and ship and coastal structure design in future versions.

5 Aug 2022

South Pole Station Snowdrift Model

Abstract: The elevated building at Scott-Amundsen South Pole Station was designed to mitigate the effects of windblown snow on it and the surrounding infrastructure. Because the elevation of the snow surface increases annually, the station is periodically lifted on its support columns to maintain its design height above the snow surface. To assist with planning these lifts, this effort developed a computational model to simulate snowdrift formation around the elevated building. The model uses computational fluid dynamics methods and synthetic wind record generation derived from statistical analysis of meteorological data. Simulations assessed the impact of several options for the lifting operation on drifts surrounding the elevated building. Simulation results indicate that raising the eastern-most building section (Pod A), or the entire station all at once, can reduce drift accumulation rates over the nearby arches structures. Long-term analyses, spanning 5–6 years, determine whether an equilibrium drift condition may be reached after a long period of undisturbed drift development. These simulations showed that after about 6 years, the rate of growth of the upwind drift slows, appearing to approach an equilibrium condition. However, the adjacent drifts were still increasing in depth at a roughly linear rate, indicating that equilibrium for those drifts was still several seasons away.

5 Aug 2022

SAGE-PEDD Theory Manual: Modeling Windblown Snow Deposition around Buildings

Abstract: Numerical modeling of snowdrifting is a useful tool for assessing the im-pact of building design on operations and facility maintenance. Here we outline the theory for the SAGE-PEDD snowdrift model that has applica-tion for determining snowdrift accumulation around buildings. This model uses the SAGE computational fluid dynamics code to determine the flow field in the computational domain. A particle entrainment, dis-persion, and deposition (PEDD) model is coupled to SAGE to simulate the movement and deposition of the snow within the computational do-main. The report also outlines areas of future development that upgrades to the SAGE-PEDD model should address.

5 Aug 2022

SAGE-PEDD User Manual

Abstract: SAGE-PEDD is a computational model for estimating snowdrift shapes around buildings. The main inputs to the model are wind speed, wind direction, building geometry and initial ground or snow-surface topography. Though developed mainly for predicting snowdrift shapes, it has the flexibility to accept other soil types, though this manual addresses snow only. This manual provides detailed information for set up, running, and viewing the output of a SAGE-PEDD simulation.

26 Jul 2022

The Forefront : A Review of ERDC Publications, Summer 2022

Abstract: : As the main research and development organization for the US Army Corps of Engineers (USACE), the Engineer Research and Development Center (ERDC) helps solve our nation’s most challenging problems. With seven laboratories under the ERDC umbrella, ERDC expertise spans a wide range of disciplines. This provides researchers an amazing network of collaborators both within labs and across them. Many of the publications produced by ERDC through the Information Technology Laboratory’s Information Science and Knowledge Management Branch (ISKM), the publishing authority for ERDC, are a testament to the power of these partnerships. Therefore, in this issue of The Forefront, we wanted to highlight some of those collaborations, across ERDC and beyond. Colored flags at the top of each page indicate the laboratories involved in each report (see the end of this issue for a full list of the laboratories and their lab colors), in addition to USACE red for district collaborators and gray for others. Through these collaborations, ERDC is continuing to demonstrate its value nationally and internationally. Questions about the reports highlighted in The Forefront or others published by ERDC? Contact the ISKM virtual reference desk at erdclibrary@ask-a-librarian.info or visit ERDC Knowledge Core, ISKM’s online repository, at https://erdc-library.erdc.dren.mil/. For general questions about editing and publishing at ERDC, you are also welcome to reach out to me at Emily.B.Moynihan@usace.army.mil. We look forward to continuing to be a resource for ERDC and seeing all the remarkable research that is yet to come.

20 Jul 2022

Leveraging Production Visualization Tools In Situ

Abstract: The visualization community has invested decades of research and development into producing large-scale production visualization tools. Although in situ is a paradigm shift for large-scale visualization, much of the same algorithms and operations apply regardless of whether the visualization is run post hoc or in situ. Thus, there is a great benefit to taking the large-scale code originally designed for post hoc use and leveraging it for use in situ. This chapter describes two in situ libraries, Libsim and Catalyst, that are based on mature visualization tools, VisIt and ParaView, respectively. Because they are based on fully featured visualization packages, they each provide a wealth of features. For each of these systems we outline how the simulation and visualization software are coupled, what the runtime behavior and communication between these components are, and how the underlying implementation works. We also provide use cases demonstrating the systems in action. Both of these in situ libraries, as well as the underlying products they are based on, are made freely available as open-source products. The overviews in this chapter provide a toehold to the practical application of in situ visualization.

12 Jul 2022

A Tutorial on the Rapid Distortion Theory Model for Unidirectional, Plane Shearing of Homogeneous Turbulence

Abstract: The theory of near-surface atmospheric wind noise is largely predicated on assuming turbulence is homogeneous and isotropic. For high turbulent wavenumbers, this is a fairly reasonable approximation, though it can introduce non-negligible errors in shear flows. Recent near-surface measurements of atmospheric turbulence suggest that anisotropic turbulence can be adequately modeled by rapid-distortion theory (RDT), which can serve as a natural extension of wind noise theory. Here, a solution for the RDT equations of unidirectional plane shearing of homogeneous turbulence is reproduced. It is assumed that the time-varying velocity spectral tensor can be made stationary by substituting an eddy-lifetime parameter in place of time. General and particular RDT evolution equations for stochastic increments are derived in detail. Analytical solutions for the RDT evolution equation, with and without an effective eddy viscosity, are given. An alternative expression for the eddy-lifetime parameter is shown. The turbulence kinetic energy budget is examined for RDT. Predictions by RDT are shown for velocity (co)variances, one-dimensional streamwise spectra, length scales, and the second invariant of the anisotropy tensor of the moments of velocity. The RDT prediction of the second invariant for the velocity anisotropy tensor is shown to agree better with direct numerical simulations than previously reported.

5 Apr 2022

A Dynamic Hyperbolic Surface Model for Responsive Data Mining

Abstract: Data management systems impose structure on data via a static representation schema or data structure. Information from the data is extracted by executing queries based on predefined operators. This paradigm restricts the searchability of the data to concepts and relationships that are known or assumed to exist among the objects. While this is an effective and efficient means of retrieving simple information, we propose that such a structure severely limits the ability to derive breakthrough knowledge that exists in data under the guise of “unknown unknowns.” A dynamic system will alleviate this dependence, allowing theoretically infinite projections of the data to reveal discoverable relationships that are hidden by traditional use case-driven, static query systems. In this paper, we propose a framework for a data-responsive query algebra based on a dynamic hyperbolic surface model. Such a model could provide more intuitive access to analytics and insights from massive, aggregated datasets than existing methods. This model will significantly alter the means of addressing the underlying data by representing it as an arrangement on a dynamic, hyperbolic plane. Consequently, querying the data can be viewed as a process similar to quantum annealing, in terms of characterizing data representation as an energy minimization problem with numerous minima.

4 Apr 2022

Risk-Based Prioritization of Operational Condition Assessments: Jennings Randolph Case Study

Abstract: The US Army Corps of Engineers (USACE) operates, maintains, and manages over $232 billion worth of the Nation’s water resource infrastructure. Using Operational Condition Assessments (OCA), the USACE allocates limited resources to assess asset condition in efforts to minimize risks associated with asset performance degradation, but decision makers require a greater understanding of those risks. The analysis of risk associated with Flood Risk Management assets in the context of its associated watershed system includes understanding the consequences of the asset’s failure and a determination of the likelihood that the asset will perform as expected given the current OCA ratings of critical components. This research demonstrates an application of a scalable methodology to model the probability of a dam performing as expected given the state of its subordinate gates and their components. The research team combines this likelihood with consequences generated by the application of designed simulation experiments with hydrological models to develop a measure of risk. The resulting risk scores serve as an input for an optimization program that outputs the optimal set of components to conduct OCAs on to minimize risk in the watershed. Proof-of-concept results for an initial case study on the Jennings Randolph Dam are provided.

28 Mar 2022

2020 Guided Wave Inspection of California Department of Water Resources Tainter Gate Post-Tensioned Trunnion Anchor Rods: Oroville Dam

Abstract: The Engineering and Test Branch within the Division of Operations and Maintenance of the California Department of Water Resources (DWR) and U.S. Army Corps of Engineers (USACE), Sacramento District, tasked the Sensor Integration Branch (SIB) at the Engineer Research and Development Center (ERDC) to perform non-destructive testing (NDT) on the trunnion anchor rods at Oroville Dam through the use of ultrasonic guided waves. This is the third year of this NDT. The results of the testing are presented along with qualitative analysis in determining whether a rod is in-tact or compromised. Analysis is based upon the expected results from other rods at the site, knowledge of rod response at other sites, data gathered from the trunnion rod research test bed at the ERDC, and comparison to the previous year’s effort.