About

W. Nathan Alexander is an Associate Professor in the Kevin T. Crofton Department of Aerospace and Ocean Engineering at Virginia Tech. He holds a PhD in Aerospace Engineering from Virginia Tech, earned in 2011, along with a Master’s degree in Ocean Engineering (2009) and a Bachelor’s degree in Ocean Engineering with Aerospace Engineering (2007) from the same institution. His research expertise encompasses Aero/Hydroacoustics, Fluid Dynamics, Wind Tunnel Testing, and Advanced Aeroacoustic Measurement Techniques. He is actively involved in professional service, serving as a core member of the Center for Research and Engineering in Aero/Hydrodynamic Technologies (CREATe) and participating as a reviewer for several scientific journals. His professional affiliations include the American Institute of Aeronautics and Astronautics (AIAA) and the American Society of Mechanical Engineers (ASME). Alexander has contributed to the field through his research on aero/hydroacoustics, including applications related to UAS, rotor and propeller machinery, wind turbines, wall roughness, and acoustic liners. He has also been involved in teaching courses such as Naval Architecture, Aero and Hydroacoustics, and Ocean Lab at Virginia Tech.

Research topics

• Political Science
• Social Science
• Mathematics
• Sociology
• Computer Science
• Engineering ethics
• Cell biology
• Biology
• Engineering
• Medicine
• Mathematics education
• Combinatorics
• Biochemistry
• Law
• Chemistry

Selected publications

• Stewart A L Glegg: Aeroacoustician, educator, and research leader

  International Journal of Aeroacoustics · 2026-02-05

  article

  This special issue of the Journal of Aeroacoustics is presented in honor of Prof. Stewart Glegg, and his many professional accomplishments. The enthusiasm of the many contributors to this volume, representing just a small subset of those who have benefitted from his work and collaboration, is just one indication of Stewart’s phenomenal impact. This article is an attempt to summarize Stewart’s personal and professional biography to date. His contributions to the aeroacoustics community include insightful technical advances in a surprisingly broad set of areas, extensive service particularly through his university and AIAA, and the inspiration, mentoring and advancement of many students and colleagues.

  PublisherDOI

• Experimental and Numerical Acoustic Scaling Investigation of a Low Tip Speed eVTOL Proprotor in Hover

  2025-05-20

  article

  To document noise characteristics and provide validation data for acoustic modeling of rotor systems appropriate for eVTOL/UAM aircraft, the authors performed an outdoor static test of a subscale 5-blade proprotor. The testing was carried out as part of a program to demonstrate feasibility and overall performance of a quiet proprotor system in support of the eVTOL industry. The authors designed a low-tip speed proprotor to approximate performance required by a 4-5 passenger UAM vehicle. A driving design feature was low-tip speed operation (Mtip ˜0.27) at system disk loadings of 7 to 8 psf (˜3.7 N/m2). The test article was designed as a ground adjustable pitch 5-blade proprotor, with aerodynamic and acoustic data collected in outdoor static hover testing. The test article diameter of 3 feet (0.91 m) represented a scale factor of approximately 30% to 40% compared to vehicles currently in operation or development. The aerodynamic performance in hover was consistent with other rotor systems tested in the past by the authors (Figure of Merit ˜0.72-0.75), and the effects of naturally occurring turbulence on rotor acoustics were measured using a 180-deg arc array of ground plane microphones at the Virginia Tech Drone Park test facility. The paper closes with a prop diameter scaling investigation using lattice-Boltzmann method CAA with and without atmospheric turbulence.

  PublisherDOI

• A passive, blade-mounted ultrasonic bat deterrent for wind turbines

  Applied Acoustics · 2024-11-18 · 2 citations

  articleOpen access
  PublisherOA PDFDOI

• Development of Amphibious Water Sampling Rover for Mosquito Research via Capstone project

  2024-02-07

  articleOpen access

  Abstract Mosquitos may lay eggs in shallow bodies of water near shore. Water samples may need to be collected for analysis, and manual collection of the water samples can be potentially a hazard to the personnel. For this reason, an amphibious water sampling rover was created by a capstone project team. This capstone project team was formed with five undergraduate engineering technology students. This project was started in the Spring semester of 2022 and concluded in the Fall semester of 2022. This project generated a rover, and the rover can navigate both on land and on water. And it can perform the water sample collection task. The rover can be controlled over a remote PC, and it can collect water temperature data, and the data can be sent remotely over the internet. For wireless communication, a sub-GHz LoRa module is used. The rover can also communicate over WiFi. A GUI (Graphical user interface) program was developed to collect data from the rover and to control the rover remotely. The GUI program obtains the GPS location of the rover and displays the location of the rover on a map. For the control of the rover, ROS (Robot Operating System) was utilized. A Raspberry Pi 3B+ board is used as an intelligence unit of the system. The collected samples can be brought to a laboratory for further analysis. In this paper, the details of the amphibious sampling rover and the educational lessons via this capstone project are presented.

  PublisherOA PDFDOI

• Data Science and Social Justice in the Mathematics Community

  Notices of the American Mathematical Society · 2023-09-07 · 2 citations

  articleOpen access
  PublisherDOI

• Data science and social justice in the mathematics community

  arXiv (Cornell University) · 2023-03-14 · 3 citations

  preprintOpen access

  Data science for social justice (DS4SJ) is data-scientific work that supports the liberation of oppressed and marginalized people. By nature, this work lies at the intersection of technical scholarship and activist practice. We discuss this growing efforts in DS4SJ within the broad mathematics community. We begin by defining terms and offering a series of guiding principles for engaging in critical data science work, providing examples of how these principles play out in practice. We then highlight the roles that DS4SJ can play in the scholarship and pedagogy of practicing mathematicians. We focus in particular on the engagement of early-career mathematicians in DS4SJ, which we illustrate through a series of four personal vignettes. While the primary aim of DS4SJ is to achieve impact for marginalized communities, we also argue that engagement with DS4SJ can benefit the entire mathematical ecosystem, including researchers, instructors, students, departments, institutes, and professional societies. We close with reflections on how these various actors can support ongoing efforts in data science for social justice.

  PublisherOA PDFDOI

• Beyond Ethics: Considerations for Centering Equity-Minded Data Science

  Journal of Humanistic Mathematics · 2022-07-01 · 6 citations

  articleOpen access1st authorCorresponding

  In this paper, we utilize duoethnography - a research method in which practitioners discursively interrogate the relationships between culture, context, and the mechanisms which shape individual autobiographical experiences - to explore what may be beyond ethics in the context of data science. Although ethical frameworks have the ability to reflect cultural priorities, a singular view of ethics, as we explore, often fails to speak to the multiple and diverse priorities held both within and across institutional spaces. To that end, this paper explores multiple perspectives, epistemologies, and worldviews that can collectively push researchers towards considerations of a data science education that is equity-minded both in concept and practice. Through a set of dialogues which examine our positionalities, journeys, ethics, local cultures, and accountabilities, this paper explores the contextual realities rooted in the authors’ educational settings. These conversations focus on the humanity of our students, the communities from which we come from and serve, as well as the unintentional harms and possibilities associated with the development of data science programs across institutional types. We take a set of five core questions to examine how we made, and continue to make, sense of our diverse cultural perspectives on data science education and equity with/in relation to others’ realities. Broadly, this paper seeks to offer reflections on the related but differing functions of ethics and equity in data science education.

  PublisherOA PDFDOI

• Justice through the lens of calculus: Framing new possibilities for\n diversity, equity, and inclusion

  arXiv (Cornell University) · 2021 · 9 citations

  • Computer Science
  • Sociology
  • Political Science

  In this volume, we encouraged a broad array of submissions that highlight\nissues of Diversity, Equity, and Inclusion (DEI) in introductory mathematics\nprograms with special attention to precalculus, differential calculus, and\nintegral calculus and surrounding departmental programs to support students in\nthese courses. The volume features illustrative case studies that showcase ways\nin which departments and instructors are attending to promoting diverse\nintroductory mathematics programs, achieving, or monitoring equitable student\noutcomes and experiences, and promoting inclusive teaching practices. Achieving\nand promoting DEI issues in introductory mathematics programs is not an easy\nundertaking so we encouraged submissions of models in progress, discussions of\npotential obstacles, challenges, and what departments and instructors have done\nto overcome barriers to address these issues. The volume also features thematic\nchapters that create a vision for DEI based on the illustrative case studies\nand known literature.\n

  PublisherOA PDFDOI

• Excitation of Airborne Acoustic Surface Modes Driven by a Turbulent Flow

  AIAA Journal · 2021-08-23 · 11 citations

  article

  This experiment demonstrates the generation of trapped acoustic surface waves excited by a turbulent flow source through the coupling of pressure fluctuations at the interface between an acoustic metamaterial and a flow environment. The turbulent flow, which behaves as a stochastic pressure source, was interfaced with an acoustic metasurface waveguide stationed in a quiescent environment via a single Kevlar-covered cavity, which ensured no significant disturbance to the flow. The metasurface waveguide produced an acoustic surface mode through evanescent diffractive coupling of the pressure field. This acoustic mode was trapped at the quiescent surface, with its mode dispersion determined by the surface geometry. The results of two different metasurface geometries are discussed: 1) a slotted cavity array, and 2) a meander connected cavity array, with each demonstrating a different trapped surface wave characteristic. Fourier transform and correlation analyses of spatially resolved temporal acoustic signals, measured close to the metamaterial surface, were used to construct the frequency- and wavevector-dependent acoustic mode dispersion. The results demonstrate that the flow can be used to excite acoustic surface modes and that their mode dispersion may be tailored toward realizing novel control of turbulent flow through acoustic-flow interactions.

  PublisherDOI

• Efficient Sampling of Protein Loop Regions Using Conformational Hashing Complemented with Random Coordinate Descent

  Journal of Chemical Theory and Computation · 2020-12-29 · 5 citations

  article

  construction of loop regions is an important problem in computational structural biology. Compared to regions with well-defined secondary structure, loops tend to exhibit significant conformational heterogeneity. As a result, their structures are often ambiguous when determined using experimental data obtained by crystallography, cryo-EM, or NMR. Although structurally diverse models could provide a more relevant representation of proteins in their native states, obtaining large numbers of biophysically realistic and physiologically relevant loop conformations is a resource-consuming task. To address this need, we developed a novel loop construction algorithm, Hash/RCD, that combines knowledge-based conformational hashing with random coordinate descent (RCD). This hybrid approach achieved a closure rate of 100% on a benchmark set of 195 loops in 29 proteins that range from 3 to 31 residues. More importantly, the use of templates allows Hash/RCD to maintain the accuracy of state-of-the-art coordinate descent methods while reducing sampling time from over 400 to 141 ms. These results highlight how the integration of coordinate descent with knowledge-based sampling overcomes barriers inherent to either approach in isolation. This method may facilitate the identification of native-like loop conformations using experimental data or full-atom scoring functions by allowing rapid sampling of large numbers of loops. In this manuscript, we investigate and discuss the advantages, bottlenecks, and limitations of combining conformational hashing with RCD. By providing a detailed technical description of the Hash/RCD algorithm, we hope to facilitate its implementation by other researchers.

  PublisherDOI

Frequent coauthors

• Jens Meiler

  Leipzig University

  28 shared

• J. R. Mcilhaney

  Yonsei University

  25 shared

• Leo Colom

  University of Florida

  25 shared

• Christian G. Hurst

  American Society For Engineering Education

  25 shared

• Byul Hur

  Texas A&M University

  20 shared

• Krzysztof Palczewski

  University of California, Irvine

  16 shared

• Carrie Diaz Eaton

  Bates College

  11 shared

• Ariana Mendible

  Seattle University

  10 shared

Labs

• Aerospace & Ocean Engineering LabPI

Education

• PhD Aerospace Engineering, Aerospace and Ocean Engineering

  Virginia Polytechnic Institute and State University

Awards & honors

• AIAA Aeroacoustics Technical Committee, 2016-Present