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Mechanical Engineering

Selected Works

University of Massachusetts Amherst

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Analysis Of The Induction And Wake Evolution Of An Offshore Floating Wind Turbine, Thomas Sebastian, Matthew Lackner Jan 2012

Analysis Of The Induction And Wake Evolution Of An Offshore Floating Wind Turbine, Thomas Sebastian, Matthew Lackner

Matthew Lackner

The degrees-of-freedom associated with offshore floating wind turbines (OFWTs) result in a more dynamic flow field. The resulting aerodynamic loads may be significantly influenced by these motions via perturbations in the evolving wake. This is of great interest in terms of OFWT design, placement and simulation. This study presents free vortex wake method (FVM) simulations of the NREL 5-MW wind turbine of a variety of platforms, operating in a range of wind speeds synthesized platform motion time series. Motion-induced wake perturbations are observed to affect induction. Transitions between windmill and propeller states are also observed.


The Performance Of Wind Turbine Smart Rotor Control Approaches During Extreme Loads, Matthew Lackner, Gijs A. M. Van Kuik Feb 2010

The Performance Of Wind Turbine Smart Rotor Control Approaches During Extreme Loads, Matthew Lackner, Gijs A. M. Van Kuik

Matthew Lackner

Reducing the loads experienced by wind turbine rotor blades can lower the cost of energy of wind turbines. “Smart rotor control” concepts have emerged as a solution to reduce fatigue loads on wind turbines. In this approach, aerodynamic load control devices are distributed along the span of the blade, and through a combination of sensing, control, and actuation, these devices dynamically control the blade loads. While smart rotor control approaches are primarily focused on fatigue load reductions, extreme loads on the blades may also be critical in determining the lifetime of components, and the ability to reduce these loads as ...


Uncertainty Analysis In Mcp-Based Wind Resource Assessment And Energy Production Estimation, Matthew Lackner, Anthony L. Rogers, James F. Manwell Aug 2008

Uncertainty Analysis In Mcp-Based Wind Resource Assessment And Energy Production Estimation, Matthew Lackner, Anthony L. Rogers, James F. Manwell

Matthew Lackner

This paper presents a mathematical framework to properly account for uncertainty in wind resource assessment and wind energy production estimation. A meteorological tower based wind measurement campaign is considered exclusively, in which measurecorrelate- predict is used to estimate the long-term wind resource. The evaluation of a wind resource and the subsequent estimation of the annual energy production (AEP) is a highly uncertain process. Uncertainty arises at all points in the process, from measuring the wind speed to the uncertainty in a power curve. A proper assessment of uncertainty is critical for judging the feasibility and risk of a potential wind ...


In-Situ High-Energy X-Ray Diffraction Study Of The Local Structure Of Supercooled Liquid Si, Robert Hyers, A. I. Goldman, K. F. Kelton, D. S. Robinson, J. R. Rogers, T. J. Rathz, A. K. Gangopadhyay, B. Sieve, G. W. Lee, T. H. Kim Aug 2005

In-Situ High-Energy X-Ray Diffraction Study Of The Local Structure Of Supercooled Liquid Si, Robert Hyers, A. I. Goldman, K. F. Kelton, D. S. Robinson, J. R. Rogers, T. J. Rathz, A. K. Gangopadhyay, B. Sieve, G. W. Lee, T. H. Kim

Robert Hyers

Employing the technique of electrostatic levitation, coupled with high-energy x-ray diffraction and rapid data acquisition methods, we have obtained high quality structural data more deeply into the supercooled regime of liquid silicon than has been possible before. No change in coordination number is observed in this temperature region, calling into question previous experimental claims of structural evidence for the existence of a liquid-liquid phase transition.