Education

Research Description

Dr. Granlund's long term goal is to gain a deeper understanding of separated unsteady, separated flows and develop physics-based low-order force models for maneuvering and control of air vehicles. Unsteady fluid mechanics exist in in several different areas such as helicopter rotor aerodynamics, wind turbines, Micro Air Vehicle flapping flight, high-rate maneuvering conventional aircraft, where the object is unsteady, as well as gusting air with unsteady inflow. In many of these research problems, the freestream has rarely been varied; it is usually assumed to be constant and uniform. Dr. Granlund's research expands the knowledge of how streamwise velocity fluctuations affect "standard" unsteady fluid dynamic problems.

Honors and Awards

• AIAA Associate Fellow, 2020

Publications

Experimental analysis of dual coaxial turbines in skew

Metoyer, R., Chatterjee, P., Elfering, K., Bryant, M., Granlund, K., & Mazzoleni, A. (2020), Ocean Engineering, 215, 107877. https://doi.org/10.1016/j.oceaneng.2020.107877

Heaving Inverted Wing in Extreme Ground Effect

Jacuzzi, E., & Granlund, K. (2020), JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME, 142(11). https://doi.org/10.1115/1.4047804

Lab-Scale, Closed-Loop Experimental Characterization, Model Refinement, and Validation of a Hydrokinetic Energy-Harvesting Ocean Kite

Siddiqui, A., Naik, K., Cobb, M., Granlund, K., & Vermillion, C. (2020), JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME, 142(11). https://doi.org/10.1115/1.4047825

Lift Equivalence and Cancellation for Airfoil Surge-Pitch-Plunge Oscillations

Elfering, K. H., & Granlund, K. O. (2020), AIAA JOURNAL, 58(11), 4629–4643. https://doi.org/10.2514/1.J059068

Supersonic Cavity Flow Subjected to Continuous and Transient Leading-Edge Blowing

Turpin, A. M., Chin, D., & Granlund, K. (2020, October), AIAA JOURNAL, Vol. 58, pp. 4415–4425. https://doi.org/10.2514/1.J059267

Time-Dependent Aerodynamic Loads on Single and Tandem Stores in a Supersonic Cavity

Chin, D., Turpin, A., & Granlund, K. (2020), JOURNAL OF AIRCRAFT, Vol. 57, pp. 702–714. https://doi.org/10.2514/1.C035749

Dual-Actuator Disc Theory for Turbines in Yaw

Khatri, D. N., Chatterjee, P., Metoyer, R., Mazzoleni, A. P., Bryant, M., & Granlund, K. O. (2019), AIAA JOURNAL, 57(5), 2204–2208. https://doi.org/10.2514/1.J057740

Passive flow control for drag reduction in vehicle platoons

Jacuzzi, E., & Granlund, K. (2019), JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS, 189, 104–117. https://doi.org/10.1016/j.jweia.2019.03.001

Stochastic Store Trajectory of Ice Models from a Cavity into Supersonic Flow

Chin, D., Granlund, K., Maatz, I., Schmit, R. F., & Reeder, M. F. (2019), JOURNAL OF AIRCRAFT, Vol. 56, pp. 1313–1319. https://doi.org/10.2514/1.C035104

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. https://doi.org/10.1007/s00162-017-0442-0

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Grants

Dynamic Response of the Shear Layer to Cavity Door Operation at Supersonic Speeds

US Air Force - Office of Scientific Research (AFOSR)(9/01/20 - 8/31/21)

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Dynamic Response of the Shear Layer to Cavity Door Operation at Supersonic Speeds

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

Start Date: 9/01/20

End Date: 8/31/21

Abstract

Wall-cavities exposed to high-subsonic or supersonic free streams have been studied for several decades in order to understand and model the aeroacoustic resonance effect from the unstable shear layer over the cavity impinging on the aft wall, causing recirculation and acoustic resonance. Low-order models have been developed, and suppression mechanisms have been conceived from a frequency-domain analysis of experiments. Here, we study the transient operation of the startup-shutdown of the cavity resonance by implementing sliding doors that cover the cavity with the aim to extend the aerodynamic models of cavity resonance to incorporate initial conditions in the time domain.

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Device Design and Robust Periodic Motion Control of an Ocean Kite System for Hydrokinetic Energy Harvesting

US Dept. of Energy (DOE) - Energy Efficiency & Renewable Energy (EERE)(5/01/19 - 4/30/22)

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Device Design and Robust Periodic Motion Control of an Ocean Kite System for Hydrokinetic Energy Harvesting

Sponsor: US Dept. of Energy (DOE) - Energy Efficiency & Renewable Energy (EERE)

Start Date: 5/01/19

End Date: 4/30/22

Abstract

This project will focus on the model-based design, flight characterization, robust periodic control, 1/10-scale prototyping, and testing of a rigid kite-based ocean current and tidal energy harvesting system. The system is intended for areas of moderate flow in relatively shallow waters, one example being the shallow waters adjacent to the Gulf Stream. The proposed system will consist of a high lift/drag rigid wing that executes periodic cycles. Each cycle will consist of a high-tension cross-current spool-out phase, followed by a low-tension spool-in phase. The use of multiple control tethers and/or on-board control surfaces will make it possible to achieve and control this desired periodic motion in a manner that is robust to fluctuations and uncertainties (e.g., ocean current speed/direction, etc.). It has been demonstrated that properly controlled periodic motions can lead more than an order of magnitude increase in net energy production over equivalently-sized stationary devices, or equivalently, the same amount of power as a stationary system using an order of magnitude less material. The proposed research will focus on two candidate kite-based system configurations: (i) A system where the electric motors/generators and power electronics are housed on a floating platform out of the water and (ii) a system where they are housed at the seabed, in shallower waters.

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Aerodynamic Forces on Slender Body in Supersonic Cavity

Air Force Research Laboratory (AFRL)(7/09/16 - 9/30/19)

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Aerodynamic Forces on Slender Body in Supersonic Cavity

Sponsor: Air Force Research Laboratory (AFRL)

Start Date: 7/09/16

End Date: 9/30/19

Abstract

The purpose of this project is to investigate the magnitude of lift and pitching moment variation during an unsteady vs. the quasi-steady translation of a slender body from a cavity through a vortex-shear layer into supersonic flow. Mean- and time-varying, as well as frequency content of the normal force and pitching moment will be recorded. To correlate the forces on the store, simultaneous flowfield information, as well as surface pressure data will be obtained. The future application is to investigate whether timed-release of stores from cavities offer a benefit in a more accurate prediction of safe trajectory from the air vehicle.

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