11 Jun 2021

Topological data analysis: an overview

Abstract: A growing area of mathematics topological data analysis (TDA) uses fundamental concepts of topology to analyze complex, high-dimensional data. A topological network represents the data, and the TDA uses the network to analyze the shape of the data and identify features in the network that correspond to patterns in the data. These patterns extract knowledge from the data. TDA provides a framework to advance machine learning’s ability to understand and analyze large, complex data. This paper provides background information about TDA, TDA applications for large data sets, and details related to the investigation and implementation of existing tools and environments.

11 Jun 2021

The Forefront: A Review of ERDC Publications, Spring 2021

Abstract: The Engineer Research and Development Center (ERDC) is the premier civil works engineering and environmental sciences research and development arm of the U.S. Army Corps of Engineers (USACE). As such, it partners with the Army, Department of Defense (DoD), federal agencies, and civilian organizations to help solve our Nation’s most challenging problems in civil and military engineering, geospatial sciences, water resources, and environmental sciences. A special government knowledge center, ERDC Information Technology Laboratory’s Information Science and Knowledge Management (ISKM) Branch is critical to ERDC’s mission, fulfilling research requirements by offering a variety of editing and library services to advance the creation, dissemination, and curation of ERDC and USACE research knowledge. Serving as the publishing authority for the ERDC, ISKM publishes all ERDC technical publications to the Digital Repository Knowledge Core, sends a copy to the Defense Technical Information Center (DTIC) and creates a press release about each publication on the ERDC website. The Forefront seeks to provide an additional mechanism for highlighting some of our technical publications to the ERDC, USACE, Army, and DoD communities. This publication also encourages those outside ERDC to contact us about using ERDC editing services. For more information regarding the reports highlighted in this publications or others that ERDC researchers’ have created, please contact the ISKM virtual reference desk at erdclibrary@ask-a-librarian.info or visit the ISKM’s online repository, Knowledge Core, at https://erdc-library.erdc.dren.mil/

8 Jun 2021

New capabilities in CREATE™-AV Helios Version 11

Abstract: CREATE™-AV Helios is a high-fidelity coupled CFD/CSD infrastructure developed by the U.S. Dept. of Defense for aeromechanics predictions of rotorcraft. This paper discusses new capabilities added to Helios version 11.0. A new fast-running reduced order aerodynamics option called ROAM has been added to enable faster-turnaround analysis. ROAM is Cartesian-based, employing an actuator line model for the rotor and an immersed boundary model for the fuselage. No near-body grid generation is required and simulations are significantly faster through a combination of larger timesteps and reduced cost per step. ROAM calculations of the JVX tiltrotor configuration give a comparably accurate download prediction to traditional body-fitted calculations with Helios, at 50X less computational cost. The unsteady wake in ROAM is not as well resolved, but wake interactions may be a less critical issue for many design considerations. The second capability discussed is the addition of six-degree-of-freedom capability to model store separation. Helios calculations of a generic wing/store/pylon case with the new 6-DOF capability are found to match identically to calculations with CREATE™-AV Kestrel, a code which has been extensively validated for store separation calculations over the past decade.

8 Jun 2021

Summary of the SciTech 2020 Technical Panel on In Situ/In Transit Computational Environments for Visualization and Data Analysis

Link: http://dx.doi.org/10.21079/11681/40887This paper was originally presented at the American Institute of Aeronautics and Astronautics (AIAA) ScitTech 2020 Technical Panel and published online 4 January 2021. Funding by USACE ERDC under Army Direct funding.Report Number: ERDC/ITL MP-21-10Title: Summary of the SciTech 2020 Technical Panel on In

3 Jun 2021

Finite element analysis of quoin block deterioration and load transfer mechanisms in miter gates: pintle and pintle connections

Abstract: The U.S. Army Corps of Engineers (USACE) currently operates and maintains approximately 193 commercially active lock sites with 239 locks and dams spanning nearly 12,000 miles. These networks of water channels are used to transport 600 million tons of domestic cargo, generating $405 billion in revenue annually. Nearly 60% of these structures in operation are over 50 years old and have reached design life. A failure of the miter gates could result in a major negative impact on the economy and on the ability to maintain flood control. Administrators need recommendations to better prioritize maintenance and repair of the USACE miter gates. This work investigated the influence of miter gate’s quoin block degradation on load transfer to the pintle and/or pintle connections. Results of finite element analysis are reported for the quoin block degradation simulated levels of 0%, 25%, 50%, and 75%. The parametric study shows the overstressed regions are the pintle neck and bolt-hole regions. To improve pintle designs so they may better mitigate detrimental environmental based deterioration effects, this work recommends (1) increasing the thickness of the bolt-hole connection region and (2) adding ribbing reinforcement around the neck area of the pintle.

3 Jun 2021

In situ analysis and visualization to enable better workflows with CREATE-AV™ Helio

Abstract: The CREATE-AV™ Helios CFD simulation code has been used to accurately predict rotorcraft performance under a variety of flight conditions. The Helios package contains a suite of tools that contain almost the entire set of functionality needed for a variety of workflows. These workflows include tools customized to properly specify many in situ analysis and visualization capabilities appropriate for rotorcraft analysis. In situ is the process of computing analysis and visualization information during a simulation run before data is saved to disk. In situ has been referred to with a variety of terms including co-processing, covisualization, coviz, etc. In this paper we describe the customization of the pre-processing GUI and corresponding development of the Helios solver code-base to effectively implement in situ analysis and visualization to reduce file IO and speed up workflows for CFD analysts. We showcase how the workflow enables the wide variety of Helios users to effectively work in post-processing tools they are already familiar with as opposed to forcing them to learn new tools in order post-process in situ data extracts being produced by Helios. These data extracts include various sources of information customized to Helios, such as knowledge about the near- and off-body grids, internal surface extracts with patch information, and volumetric extracts meant for fast post-processing of data. Additionally, we demonstrate how in situ can be used by workflow automation tools to help convey information to the user that would be much more difficult when using full data dumps.

3 Jun 2021

Elevation of underlying basement rock, Ogdensburg Harbor, NY

Abstract: Over six linear miles of shallow acoustic reflection geophysical data were collected in an 800 ft by 300 ft survey region at Ogdensburg Harbor, Ogdensburg, NY. To better accommodate modern commercial vessels and expand the harbor’s capacity, the current navigable depth of -19 ft Low Water Depth (LWD) needs to be increased to -28 ft LWD, and an accurate map of the nature of the riverbed material (e.g., unconsolidated sediment, partially indurated glacial till, or bedrock) is required to effectively plan for removal. A total of 28 boreholes were previously collected to map the stratigraphy, and the effort revealed significant spatial variability in unit thickness and elevation between adjacent boreholes. To accurately map this variable stratigraphy, chirp sub-bottom profiles were collected throughout the region, with an average line spacing of 13 ft. These sub-bottom data, validated and augmented by the borehole data, resulted in high-resolution spatial maps of stratigraphic elevation and thickness for the study area. The data will allow for more accurate assessment of the type and extent of different dredging efforts required to achieve a future uniform depth of -28 ft LWD for the navigable region.

2 Jun 2021

AIS data case study: quantifying connectivity for six Great Lakes port areas from 2015 through 2018

Abstract: This Coastal and Hydraulics Engineering Technical Note presents results from a preliminary examination of commercial vessel traffic connectivity between six major port areas on the Great Lakes using Automatic Identification System data collected from 2015 to 2018. The six port areas included in this study are Calumet Harbor, IL and IN; Cleveland, OH; Detroit, MI; Duluth-Superior, MN and WI; Indiana Harbor, IN; and Two Harbors, MN. These six locations represent an important subset of the more than 100 federally authorized navigation projects in the Great Lakes maintained by the US Army Corps of Engineers. The results are presented in the context of USACE resilience-related policy initiatives as well as the larger topic of maritime system resilience.

2 Jun 2021

Multi-objective source scaling experiment

Abstract: The U.S. Army Engineer Research and Development Center (ERDC) performed an experiment at a site near Vicksburg, MS, during May 2014. Explosive charges were detonated, and the shock and acoustic waves were detected with pressure and infrasound sensors stationed at various distances from the source, i.e., from 3 m to 14.5 km. One objective of the experiment was to investigate the evolution of the shock wave produced by the explosion to the acoustic wavefront detected several kilometers from the detonation site. Another objective was to compare the effectiveness of different wind filter strategies. Toward this end, several sensors were deployed near each other, approximately 8 km from the site of the explosion. These sensors used different types of wind filters, including the different lengths of porous hoses, a bag of rocks, a foam pillow, and no filter. In addition, seismic and acoustic waves produced by the explosions were recorded with seismometers located at various distances from the source. The suitability of these sensors for measuring low-frequency acoustic waves was investigated.

28 May 2021

Challenges in evaluating efficacy of scientific visualization for usability and aesthetics

Abstract: This paper presents the results of a study to evaluate the efficacy of scientific visualization for multiple categories of users, including both domain experts as well as users from the general public. Efficacy was evaluated for understanding, usability, and aesthetic value. Results indicate that aesthetics play a critical, but complex role in enhancing both user understanding and usability.