Search results for "Wind"

Finite-element performance comparison of IPMSMs with unsymmetrical double-layer windings

2017

This paper presents a comparison of the performances between IPMSMs (Interior Permanent Magnet Synchronous Machine) with a symmetrical and with two different types of unsymmetrical windings. The aim is to demonstrate that the adoption of slightly unsymmetrical windings does not significantly affect the performances of the machines, both in terms of cogging torque and torque/load angle characteristics, providing also the advantage of a higher possibility of choice in terms of slot number/poles ratio. More in particular, an IPMSM model (named IPMSM-1) derived from a commercial geometry equipped with a symmetrical winding is analyzed by using a Finite Element Method (FEM) approach. The simulat…

Glossing wind names in Low German in Salisbury? A newly discovered text in London, British Library, Cotton Vitellius A.xii

2018

It's an essay investigating a text on the names of the winds in ms London, British Library, Cotton Vitellius A.xii (s. xi), where both Latin and vernacular names are given. The text may ultimately derive from Einhard's Life of Charlemagne (ch. 29), but it appears as a self-contained text in the form of a Class Glossary. Although inserted in a manuscript copied in England at Salisbury, the vernacular words of the text are not in Old English. The essay makes a case for a possible connection with Flanders, with the text being one of the very rare surviving specimen of the Old Low Franconian language.

Second-order hydrodynamic effects on the response of three semisubmersible floating offshore wind turbines

2020

Abstract Floating structures have become the most feasible solution for supporting wind turbines when offshore wind project move to deeper water. In this paper, a hydrodynamic analysis of three different semisubmersible floating offshore wind turbines is carried out including second-order hydrodynamic effects. The three examined platforms are V-shaped semisubmersible, Braceless semisubmersible and OC4-DeepCwind semisubmersible and are used to support the NREL 5 MW reference wind turbine. The main objective of the present study is to investigate and compare the hydrodynamic response of the three different semisubmersible floaters in two water depths (100 m, and 200 m) under different load co…

Yacht performance monitoring in real sailing conditions

2019

Abstract In this paper a multi-method approach is used to setup and validate a monitoring system applied to a small sailing boat during real sailing conditions. This monitoring system is able to transform the data coming from some typical devices installed on board into information about the deformed state of the boat. GPS, Wind Data Logger and cameras have been installed on the boat to measure its route and speed, the apparent wind velocity and direction and the positions of the crew members. These data are processed to determine the equilibrium of the boat and estimate the loads applied on it. Then, a CAD/FEM model calculates the effects of these loads on the boat shape. The resulting def…

Transient response of a TLP-type floating offshore wind turbine under tendon failure conditions

2021

Abstract Among various types of floating offshore wind turbines (FOWTs), the tension leg platform (TLP) floating wind turbines have relatively small motions due to stiff tendons. Similar to TLP applications in the offshore industry, tendon failure may lead to deteriorated stability and large transient responses, which should be considered as part of accidental limit state (ALS) checks at the design stage of the TLP FOWTs. This paper takes the WindStar TLP system as a representative and investigates the transient effects of one-tendon failure on the system responses. A coupled numerical model is first established using the aero-hydro-servo-elastic simulation tool FAST. Subsequent numerical s…

Windrow composting of source separated kitchen biowastes in Finland

2000

All households in the City of Jyväskylä have been required to source-separate their wastes since June 1996. The accumulation of kitchen biowaste was about 60 kg per resident in 1997, with an efficiency of more than 75%. The residents of almost 50% of the detached houses in the city opted for small-scale composting. Ensuing kitchen biowaste was surprisingly pure: the estimated content of non-compostable material was less than 0.1 % by weight. The biowastes were composted at the Mustankorkea waste station in open windrows. Adequate aeration of the windrows was guaranteed when the initial height of the windrow was less than 1.5 m and the blending ratio for biowaste and bulking agent was one t…

Evoluzione di una turbina eolica innovativa

The Application of Different Model of Multi-Layer Perceptrons in the Estimation of Wind Speed

2012

Wind speed forecasting is essential for effective planning of wind energy exploitation projects. The ability to predict short-term wind speed is a prerequisite for all the operators of the wind energy sector. Consequently it is essential to identify an efficient method for forecasts. In this paper, the wind speed in the province of Trapani (Sicily) is modeled by artificial neural network. Several model of neural network were generated and compared through error measures. Simulation results show that the estimated values of wind speed are in good agreement with the values measured by anemometers..

Estimation of Daily Solar Radiation from Measured Air Temperature Extremes in the Mid-Mediterranean Area

2012

AbstractDaily solar radiation Rs at ground level is a necessary input variable required for the evaluation of evapotranspiration and crop growth, development, and yield-simulation models. Nevertheless, it is measured in few weather stations and at many locations it is not observed; also, available Rs temporal series are generally no longer than a few years. A valid surrogate of Rs measurement is the diurnal air-temperature range (ΔT); indeed, ΔT is inversely proportional to cloudiness and therefore could be a good indicator of atmospheric transmittance. As opposed to Rs, daily maximum and minimum air temperatures are measured at many locations and their observations in developed countries b…

Estimación de la temperatura superficial del mar desde datos satelitales NOAA-AVHRR: validación de algoritmos aplicados a la costa norte de Chile

2011

Se aplicaron y compararon tres algoritmos del tipo Split-Window (SW), que permitieron estimar la temperatura superficial del mar desde datos aportados por el sensor Advanced Very High Resolution Radiometer (AVHRR), a bordo de la serie de satélites de la National Oceanic and Atmospheric Administration (NOAA). La validación de los algoritmos fue lograda por comparación con mediciones in situ de temperatura del mar provenientes de una boya hidrográfica, ubicada frente a la costa norte de Chile (21°21'S, 70°6'W; Región de Tarapacá), a 3 km de la costa aproximadamente. Los mejores resultados se obtuvieron por aplicación del algoritmo propuesto por Sobrino & Raissouni (2000). En efecto, diferenci…