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Full-Text Articles in Engineering

Polynomial Chaos For The Computation Of Annual Energy Production In Wind Farm Layout Optimization, Santiago Padrón, Andrew P.J. Stanley, Jared Thomas, Juan Alonso, Andrew Ning Oct 2016

Polynomial Chaos For The Computation Of Annual Energy Production In Wind Farm Layout Optimization, Santiago Padrón, Andrew P.J. Stanley, Jared Thomas, Juan Alonso, Andrew Ning

Faculty Publications

Careful management of wake interference is essential to further improve Annual Energy Production (AEP) of wind farms. Wake effects can be minimized through optimization of turbine layout, wind farm control, and turbine design. Realistic wind farm optimization is challenging because it has numerous design degrees of freedom and must account for the stochastic nature of wind. In this paper we provide a framework for calculating AEP for any relevant uncertain (stochastic) variable of interest. We use Polynomial Chaos (PC) to efficiently quantify the effect of the stochastic variables—wind direction and wind speed—on the statistical outputs of interest (AEP) for wind …


A Hybrid Optimization Technique Applied To The Intermediate-Target Optimal Control Problem, Clay J. Humphreys, Richard G. Cobb, David R. Jacques, Jonah A. Reeger Aug 2016

A Hybrid Optimization Technique Applied To The Intermediate-Target Optimal Control Problem, Clay J. Humphreys, Richard G. Cobb, David R. Jacques, Jonah A. Reeger

Faculty Publications

The DoD has introduced the concept of Manned-Unmanned Teaming, a subset of which is the loyal wingman. Optimal control techniques have been proposed as a method for rapidly solving the intermediate-target (mid-point constraint) optimal control problem. Initial results using direct orthogonal collocation and a gradient-based method for solving the resulting nonlinear program reveals a tendency to converge to or to get `stuck’ in locally optimal solutions. The literature suggested a hybrid technique in which a particle swarm optimization is used to quickly find a neighborhood of a more globally minimal solution, at which point the algorithm switches to a gradient-based …


Thermal Transport Properties Of Dry Spun Carbon Nanotube Sheets, Heath E. Misak, James L. Rutledge, Eric D. Swenson, Shankar Mall Feb 2016

Thermal Transport Properties Of Dry Spun Carbon Nanotube Sheets, Heath E. Misak, James L. Rutledge, Eric D. Swenson, Shankar Mall

Faculty Publications

The thermal properties of carbon nanotube- (CNT-) sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an …


Development Of Cloud-Based Uav Monitoring And Management System, Mason Itkin, Mihui Kim, Younghee Park Jan 2016

Development Of Cloud-Based Uav Monitoring And Management System, Mason Itkin, Mihui Kim, Younghee Park

Faculty Publications

Unmanned aerial vehicles (UAVs) are an emerging technology with the potential to revolutionize commercial industries and the public domain outside of the military. UAVs would be able to speed up rescue and recovery operations from natural disasters and can be used for autonomous delivery systems (e.g., Amazon Prime Air). An increase in the number of active UAV systems in dense urban areas is attributed to an influx of UAV hobbyists and commercial multi-UAV systems. As airspace for UAV flight becomes more limited, it is important to monitor and manage many UAV systems using modern collision avoidance techniques. In this paper, …


Aerodynamic Modeling Of Nrel 5-Mw Wind Turbine For Nonlinear Control System Design: A Case Study Based On Real-Time Nonlinear Receding Horizon Control, Pedro A. Galvani, Fei Sun, Kamran Turkoglu Jan 2016

Aerodynamic Modeling Of Nrel 5-Mw Wind Turbine For Nonlinear Control System Design: A Case Study Based On Real-Time Nonlinear Receding Horizon Control, Pedro A. Galvani, Fei Sun, Kamran Turkoglu

Faculty Publications

The work presented in this paper has two major aspects: (i) investigation of a simple, yet efficient model of the NREL (National Renewable Energy Laboratory) 5-MW reference wind turbine; (ii) nonlinear control system development through a real-time nonlinear receding horizon control methodology with application to wind turbine control dynamics. In this paper, the results of our simple wind turbine model and a real-time nonlinear control system implementation are shown in comparison with conventional control methods. For this purpose, the wind turbine control problem is converted into an optimization problem and is directly solved by the nonlinear backwards sweep Riccati method …


Constructal Alkaline Membrane Fuel Cell (Amfc) Design, E. M. Sommer, J. V. C. Vargas, Lauber De Souza Martins, J. C. Ordonez Jan 2016

Constructal Alkaline Membrane Fuel Cell (Amfc) Design, E. M. Sommer, J. V. C. Vargas, Lauber De Souza Martins, J. C. Ordonez

Faculty Publications

This paper introduces a structured procedure to optimize the internal structure (relative sizes, spacing) and external shape (aspect ratios) of a single alkaline membrane fuel cell so that net power is maximized. The optimization of flow geometry is conducted for the smallest (elemental) level of a fuel cell stack, i.e., the single alkaline membrane fuel cell, which is modeled as a unidirectional flow system. The polarization curve, total and net power, and efficiency are obtained as functions of temperature, pressure, electrolyte solution concentration (KOH), geometry and operating parameters. The optimization is subjected to fixed total volume. There are two levels …