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2016

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Articles 9601 - 9604 of 9604

Full-Text Articles in Engineering

Aerodynamic Performance Characterization Of Leading Edge Protrusions On Small Propellers, Kevin Moore, Andrew Ning Jan 2016

Aerodynamic Performance Characterization Of Leading Edge Protrusions On Small Propellers, Kevin Moore, Andrew Ning

Faculty Publications

The relatively large tubercles or protruding bumps on the leading edge of the humpback whale fin create counter-rotating chordwise vortices. At high Reynolds numbers, these vortices have been shown to delay stall with minimal effect on drag. The range of Reynolds numbers that these types of vortices form is unknown, and so an investigation of the potential for an increased envelope of operation for small aircraft propellers was done. For the cases tested in this report no benefits were observed. The addition of leading edge protrusions decreased propeller performance in both efficiency and thrust. Because of the inherent restrictions on …

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Optimization-Based Path Planning For Separation Assurance On Small Unmanned Aircraft, Matthew Duffield, Andrew Ning, Timothy Mclain Jan 2016

Optimization-Based Path Planning For Separation Assurance On Small Unmanned Aircraft, Matthew Duffield, Andrew Ning, Timothy Mclain

Faculty Publications

This paper presents a time-based path planning optimizer for separation assurance for unmanned aircraft systems (UAS). Given Automatic Dependent Surveillance-Broadcast (ADS-B) as a sensor, intruder information such as position, velocity, and identification information is available at ranges on the order of 50 nautical miles. Such long-range intruder detection facilitates path planning for separation assurance, but also poses computational challenges. The time-based path optimizer presented in this paper provides a path-planning method that takes advantage of long-range ADS-B information and addresses the associated challenges. It is capable of long-range path planning and, due to the convex formulation, is computationally efficient enough …

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Parameterized Vertical-Axis Wind Turbine Wake Model Using Cfd Vorticity Data, Andrew Ning, Eric Tingey Jan 2016

Parameterized Vertical-Axis Wind Turbine Wake Model Using Cfd Vorticity Data, Andrew Ning, Eric Tingey

Faculty Publications

In order to analyze or optimize a wind farm layout, reduced-order wake models are often used to estimate the interactions between turbines. While many such models exist for horizontal-axis wind turbines, for vertical-axis wind turbines (VAWTs) a simple parametric wake model does not exist. Using computational fluid dynamic (CFD) simulations we computed vorticity in a VAWT wake, and parameterized the data based on normalized downstream positions, tip-speed ratio, and solidity to predict a normalized wake velocity deficit. When compared to CFD, which takes about a day to run one simulation, the reduced-order model predicts the velocity deficit at any location …

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Landing Zone Determination For Autonomous Rotorcraft In Surveillance Applications, Timothy Mclain, Gary J. Ellingson, Justin Mackay Jan 2016

Landing Zone Determination For Autonomous Rotorcraft In Surveillance Applications, Timothy Mclain, Gary J. Ellingson, Justin Mackay

Faculty Publications

This paper presents an approach for finding possible landing sites for a rotorcraft from an inertially referenced point-cloud model of the environment. To identify potential landing sites that are suitably flat and level, a grid-based random sample consensus algorithm separates the terrain map into discrete areas for plane-fitting analysis. Landing sites are selected that satisfy constraints on flatness and levelness while optimizing the surveillance target’s visibility. Flight test results are presented from a small multirotor aircraft flying over a scale-model cityscape. Results from real-time landing-site experiments are presented and discussed.

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