Publications

Coriolis effects on wind turbine wakes across neutral atmospheric boundary layer regimes [Article]

Kirby S. Heck and Michael F. Howland*

Journal of Fluid Mechanics (2025)

Plain language summary: In this paper, we explore how wind turbine wakes, turbulent regions of low wind speeds downstream of the turbine, are affected by Coriolis effects. Because Coriolis effects are more important at larger scales, the increasing size of wind turbines changes the flow physics and turbulence around them. We find that modern offshore wind turbines, which have rotor diameters over 200 meters, will operate in different flow regimes than the previous generation of onshore utility-scale turbines. This has implications on how we model wind turbines and how we might optimally control large wind turbines in the future. 

Unified momentum model for rotor aerodynamics across operating regimes [Article]

Jaime Liew, Kirby S. Heck, and Michael F. Howland*

Nature Communications (2024)

Plain language summary: Turbines and propellers often operate in "high-thrust" conditions, where the flow around the rotor becomes very complex and turbulent. Traditional approaches to modeling high-thrust conditions rely on empirical fitting to simulation or experimental data for engineering modeling. Continuing to innovate on the modeling from our previous work, we derive a physics-based flow model for turbines and propellers that accurately predicts rotor behavior in high-thrust conditions. 

Wavelength-induced shedding frequency modulation of seal whisker inspired cylinders [Article]

Trevor K. Dunt, Kirby S. Heck, and Kathleen Lyons, Christin T. Murphy, Raul Bayoán Cal, and Jennifer A. Franck*

Bioinspiration and Biomimetics (2024)

Plain language summary: Harbor seal whiskers have a complex, undulated three-dimensional geometry that contributes to their extraordinary hunting ability. The whisker geometry improves a seal's sensing ability by suppressing flow-induced vibration to improve the signal-to-noise ratio of isolating disturbances in water from their prey. Using computational simulations, we vary the undulation wavelength of idealized whisker shapes to study how geometry affects flow structures and whisker vibration frequency. Improved understanding of flow around wavy whisker geometries could be used to engineer better sensing instruments or suppress the vibration of mooring cables, chimneys, or other structures. 

Modelling the induction, thrust and power of a yaw-misaligned actuator disk [Article]

Kirby S. Heck, Hannah M. Johlas, and Michael F. Howland*

Journal of Fluid Mechanics (2023)

Plain language summary: Traditional modeling of turbines assumes that the fluid flow through the rotor is directly aligned with the rotor face. Any misalignment with the rotor causes these classical approaches to become invalid, and engineers have historically relied on empirical models (data-driven fits) to explain rotor behavior in cases of misalignment. In this paper, we derive a physics-based, analytical model to describe flow around rotors in misaligned conditions. Using a physics-based approach decreases reliance on empirical data fitting and extrapolates better to out-of-sample designs.