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Mechanical Engineering

Portland State University

Theses/Dissertations

Wind power -- Mathematical models

Publication Year

Articles 1 - 2 of 2

Full-Text Articles in Engineering

Characterizing Tilt Effects On Wind Plants, Ryan Scott Jun 2019

Characterizing Tilt Effects On Wind Plants, Ryan Scott

Dissertations and Theses

Tilting the nacelle of a wind turbine modifies entrainment into the wind plant and impacts total efficiency. Extreme angles can produce flying and crashing wakes where the wake either disrupts entertainment from the undisturbed flow above or is decimated on the ground. The effect of tilt angle on downstream wake behavior was investigated in a series of wind tunnel experiments. Scale model turbines with a hub height and diameter of 12 cm were arranged in a Cartesian array comprised of four rows of three turbines each. Nacelle tilt was varied in the third row from -15° to 15° in chosen …


Identification Of Markov Processes Within A Wind Turbine Array Boundary Layer, Matthew Scott Melius Aug 2013

Identification Of Markov Processes Within A Wind Turbine Array Boundary Layer, Matthew Scott Melius

Dissertations and Theses

The Markovianity within a wind turbine array boundary layer is explored for data taken in a wind tunnel containing a model wind turbine array. A stochastic analysis of the data is carried out using Markov chain theory. The data were obtained via hot-wire anemometry thus providing point velocity statistics. The theory of Markovian processes is applied to obtain a statistical description of longitudinal velocity increments inside the turbine wake using conditional probability density functions. It is found that two and three point conditional probability density functions are similar for scale differences larger than the Taylor micro-scale. This result is quantified …