The Vertical Axis Wind Turbines (VAWTs) have an increasing global market and this emphasis the need for to improve performance of VAWTs, especially at relatively low wind speed. This paper utilises Response Surface methodology optimise a VAWT. A three bladed VAWT configuration was considered with NACA0015 profile. Three significant input parameters were selected including tip speed ratio, turbi...

Modern designs for straight-bladed vertical axis wind turbines (VAWTs)feature smaller individual footprints than conventional horizontal axis wind turbines (HAWTs), allowing closer spacing of turbines and potentially greater power extraction for the same wind farm footprint. However, the wakes of upstream turbines could persist far enough to affect the performance of closely-spaced downstream t...

In combinatorics on words, a word w over an alphabet Σ is said to avoid a pattern p over an alphabet ∆ if there is no factor f of w such that f = h(p) where h : ∆∗ → Σ∗ is a non-erasing morphism. A pattern p is said to be k-avoidable if there exists an infinite word over a k-letter alphabet that avoids p. A pattern is said to be doubled if no variable occurs only once. Doubled patterns with at ...

We propose a method to control the number of species of lattice fermions, which yields new classes of minimally doubled lattice fermions. We show it is possible to control the number of species by handling OðaÞ Wilson-term-like corrections in fermion actions, which we will term ‘‘twisted-ordering method’’. Using this method we obtain new minimally doubled actions with one exact chiral symmetry ...

We develop a green light source with low spatial coherence via intracavity frequency doubling of a solid-state degenerate laser. The second-harmonic emission supports many more transverse modes than the fundamental emission, and exhibits lower spatial coherence. A strong suppression of speckle formation is demonstrated for both fundamental and second-harmonic beams. Using the green emission for...

Recently, wind farms consisting of clusters closely spaced vertical-axis turbines (VAWTs) have attracted the interest many people. In this study, a method using wake model to predict flow field and output power each rotor in VAWT cluster is proposed. The uses information obtained by preliminary computational fluid dynamics (CFD) targeting an isolated single two-dimensional (2D) few layouts pair...