Education

Research Description

Dr. Gopalarathnam is presently 1) developing adaptive aerodynamics for morphing aircraft, 2) developing aerodynamic prediction techniques for flight dynamics simulations, and 3) studying unsteady and post-stall aerodynamics of aircraft, helicopters, micro-aerial vehicles, and flight in nature. In MAE, Dr. G works with Dr. Edwards, Dr. Wu, and Dr. Peters.

Publications

Design and demonstration of a seabird-inspired fixed-wing hybrid UAV-UUV system

Stewart, W., Weisler, W., MacLeod, M., Powers, T., Defreitas, A., Gritter, R., … Bryant, M. (2018), BIOINSPIRATION & BIOMIMETICS, 13(5). https://doi.org/10.1088/1748-3190/aad48b

Leading-edge flow criticality as a governing factor in leading-edge vortex initiation in unsteady airfoil flows

Ramesh, K., Granlund, K., Ol, M. V., Gopalarathnam, A., & Edwards, J. R. (2018), Theoretical and Computational Fluid Dynamics, 32(2), 109–136.

Testing and Characterization of a Fixed Wing Cross-Domain Unmanned Vehicle Operating in Aerial and Underwater Environments

Weisler, W., Stewart, W., Anderson, M. B., Peters, K. J., Gopalarathnam, A., & Bryant, M. (2018), IEEE JOURNAL OF OCEANIC ENGINEERING, 43(4), 969–982. https://doi.org/10.1109/JOE.2017.2742798

Computational aerodynamic modeling tools for aircraft loss of control

Frink, N. T., Murthy, P. C., Atkins, H. L., Viken, S. A., Petrilli, J. L., Gopalarathnam, A., & Paul, R. C. (2017), Journal of Guidance Control and Dynamics, 40(4), 789–803.

Piezoelectric floating element shear stress sensor for the wind tunnel flow measurement

Kim, T., Saini, A., Kim, J., Gopalarathnam, A., Zhu, Y., Palmieri, F. L., … Jiang, X. N. (2017), IEEE Transactions on Industrial Electronics, 64(9), 7304–7312.

A piezoelectric shear stress sensor

Kim, T., Saini, A., Kim, J., Gopalarathnam, A., Zhu, Y., Palmieri, F. L., … Jiang, X. N. (2016), In Sensors and smart structures technologies for civil, mechanical, and aerospace systems 2016 (Vol. 9803).

Development and testing of a passive variable-pitch propeller

Heinzen, S. B., Hall, C. E., & Gopalarathnam, A. (2015), Journal of Aircraft, 52(3), 748–763.

Limit-cycle oscillations in unsteady flows dominated by intermittent leading-edge vortex shedding

Ramesh, K., Murua, J., & Gopalarathnam, A. (2015), Journal of Fluids and Structures, 55, 84–105.

Discrete-vortex method with novel shedding criterion for unsteady aerofoil flows with intermittent leading-edge vortex shedding

Ramesh, K., Gopalarathnam, A., Granlund, K., Ol, M., & Edwards, J. (2014), Journal of Fluid Mechanics, 751.

Drag reduction on aircraft configurations with adaptive lifting surfaces

Cusher, A. A., & Gopalrathnam, A. (2014), Aerospace Science and Technology, 34, 35–44.

View all publications via NC State Libraries

Grants

Development of a Fast Low-Order Aerodynamic Prediction Method for Aircraft Configurations in Post-Stall Flight

National Aeronautics & Space Administration (NASA)(1/01/18 - 8/15/18)

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Development of a Fast Low-Order Aerodynamic Prediction Method for Aircraft Configurations in Post-Stall Flight

Sponsor: National Aeronautics & Space Administration (NASA)

Start Date: 1/01/18

End Date: 8/15/18

Abstract

The research proposed in this effort aims to combine the prediction techniques and knowledge gained from the past efforts into developing a fast low-order aerodynamic prediction method for full-aircraft configurations (wing+tails+fuselage) and assess the suitability of this method for use in real-time simulation of flight dynamics.

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Further Aerodynamic Modeling of Aerial Refueling Tanker and Receiver Interactions

US Navy(10/16/17 - 4/17/19)

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Further Aerodynamic Modeling of Aerial Refueling Tanker and Receiver Interactions

Sponsor: US Navy

Start Date: 10/16/17

End Date: 4/17/19

Abstract

In this project we will continue further research on aerodynamic modeling of close formation flight of aircraft and their interactions.

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Aerodynamic and Aeroelastic Behavior of Wings in the Presence of Upstream Vortical and Viscous Disturbances

US Air Force - Office of Scientific Research (AFOSR)(7/01/17 - 6/30/19)

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Aerodynamic and Aeroelastic Behavior of Wings in the Presence of Upstream Vortical and Viscous Disturbances

Sponsor: US Air Force - Office of Scientific Research (AFOSR)

Start Date: 7/01/17

End Date: 6/30/19

Abstract

In this research, we propose to study the effects of upstream vortical and viscous flow disturbances on the unsteady aerodynamics of airfoils undergoing prescribed motions and on the aeroelastic characteristics of flexible airfoils.

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Aerodynamic Modeling of Aerial Refueling Tanker and Receiver Interactions

US Navy(6/02/16 - 8/28/17)

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Aerodynamic Modeling of Aerial Refueling Tanker and Receiver Interactions

Sponsor: US Navy

Start Date: 6/02/16

End Date: 8/28/17

Abstract

In this research effort, we will develop a vortex lattice method for determining the incremental loads on one aircraft flying in the vicinity of another, for the purposes of developing aerodynamic models for simulation.

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CFD and Experimental Studies to Aid Development of Low-Order Aerodynamic Prediction Methods for Post-Stall Flight

National Aeronautics & Space Administration (NASA)(1/01/16 - 9/15/17)

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CFD and Experimental Studies to Aid Development of Low-Order Aerodynamic Prediction Methods for Post-Stall Flight

Sponsor: National Aeronautics & Space Administration (NASA)

Start Date: 1/01/16

End Date: 9/15/17

Abstract

We propose the development of low-order aerodynamic prediction methods for aircraft configurations at post-stall conditions, using computational fluid dynamics to help guide the development.

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Angelfish: Initial Planning and Project Management

Defense Advanced Research Projects Agency (DARPA)(6/19/14 - 1/31/16)

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Angelfish: Initial Planning and Project Management

Sponsor: Defense Advanced Research Projects Agency (DARPA)

Start Date: 6/19/14

End Date: 1/31/16

Abstract

The objective of Project Angelfish is to develop a dual-purpose (air and water) unmanned system, referred to as Angelfish. The system to be developed will be capable of locomotion and controlled maneuvering in both the aerial and subsurface domains. The air-purpose performance (flight distance, duration, etc.) is to be minimally compromised by the water-purpose requirements, and the transition between air and water are to be as reliable as possible, again with minimal performance penalty (power). The goal of the effort is to develop alternative designs that lie throughout the trade space and to focus the further development on the most promising design or set of designs.

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Evaluation of Flexible Micropost Arrays for Shear Stress Measurement

National Aeronautics & Space Administration (NASA)(7/10/14 - 7/09/16)

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Evaluation of Flexible Micropost Arrays for Shear Stress Measurement

Sponsor: National Aeronautics & Space Administration (NASA)

Start Date: 7/10/14

End Date: 7/09/16

Abstract

Micropillar arrays will be developed for shear stress measurement in NCSU subsonic wind tunnel. Micropillar array sensors will be characterized first, and then assembled into a test model and calibrated in the wind tunnel. Such a measurement device enables new aerodynamics research needed to design more fuel efficient, quieter aircraft with improved dynamics for smoother and safer flight.

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Aerodynamic Sensing using Miniature Transducers

General Electric Co.(3/01/13 - 12/31/13)

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Aerodynamic Sensing using Miniature Transducers

Sponsor: General Electric Co.

Start Date: 3/01/13

End Date: 12/31/13

Abstract

In this project we will develop aerodynamic sensing on an airfoil using miniature pressure transducers.

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Harnessing Fluid-Structure Interaction in Wind Power and Sustainable Air Transport

University Global Partnership Network (UGPN)(3/01/13 - 2/28/14)

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Harnessing Fluid-Structure Interaction in Wind Power and Sustainable Air Transport

Sponsor: University Global Partnership Network (UGPN)

Start Date: 3/01/13

End Date: 2/28/14

Abstract

A research collaboration between Dr Joseba Murua (University of Surrey) and Prof Ashok Gopalarathnam (North Carolina State University) is hereby proposed for the second call for proposals of the University Global Partnership Network (UGPN). The collaboration will tackle the multi-physics interaction between fluids and structures, focusing on the development of design-oriented modelling tools applicable to both wind turbines and aerospace vehicles. The aerodynamic efficiency of aircraft and wind turbines can be maximised using low-weight and slender wings/blades operating at conditions just short of aerodynamic stall. However, light, slender and thus flexible structures exhibit coupled fluid-structure behaviour, increasing the likelihood of reaching stall, a sub-optimal flow regime. A design-oriented computational tool that captures this fluid-structure interaction and accounts for stall is proposed, integrating the so-called decambering approach into a flexible aircraft model. The resulting multidisciplinary framework will be applicable to a wide range of current and novel systems in both aerospace and wind power, filling a niche area for fast yet accurate simulation capability. The project will be based on the placement of a PhD student, and the outcome of the research will be published in a flagship international aerospace conference and a high-impact journal. The project is also expected to establish the foundations of a long-term collaboration that will focus on exploiting fluid-structure interaction to optimise aerodynamic performance in next-generation technologies.

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Theoretical and Computational Modeling of Two-Dimensional and Three-Dimensional Dynamic Stall for Rotorcraft Applications

US Army - Army Research Office(3/15/13 - 12/31/16)

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Theoretical and Computational Modeling of Two-Dimensional and Three-Dimensional Dynamic Stall for Rotorcraft Applications

Sponsor: US Army - Army Research Office

Start Date: 3/15/13

End Date: 12/31/16

Abstract

In this project, we will computational fluid dynamics studies of two-dimensional and three-dimensional simulations of dynamic stall to guide the development of low-order prediction methods and to gain insight into the flow physics.

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