Search results for "wind"

HIGH-EFFICIENCY OSCILLATING-BLADE WIND TURBINE

2011

Fractional calculus approach for the representation of power spectral densities and correlation functions in wind engineering

2010

The paper deals with the digital simulation of wind velocity samples by Fractional Spectral Moment function. It is shown that such a function represents a third useful way to characterize a stationary Gaussian stochastic process, alongside the power spectral density and the correlation function. The method is applied to wind velocity fields whose power spectra is given by the Kaimal’s, the Davenport’s and the Solari’s representation. It is shown that by constructing a digital filter whose coefficients are the fractional spectral moments, it is possible to simulate samples of the target process as superposition of Riesz fractional derivatives of Gaussian white noise processes.

Univariate and multivariate properties of wind velocity time series

2009

We analyze the time series of hourly average wind speeds measured at 29 different stations located in Sicily, a region with a complex morphology. The investigation, performed from the univariate as well as the multivariate point of view, evidences that the statistical properties of wind at the single sites have features that are not reproduced by standard models and, thus, require specific modeling. Moreover, the synchronous evolution of wind velocity presents a cluster structure, obtained with different algorithms, that persists in the standard deviation too.

Wind- and tide-induce currents in the Stagnone Lagoon (Sicily)

2009

Persistency of window dressing practices in the US repo markets after the GFC: The unexplored role of the deposit insurance premium

2022

We investigate whether the regulatory improvements made in the aftermath of the global financial crisis have been effective in limiting bank downward window dressing by means of repos in the United States. We find that a strict application of the Basel III regulation wipes out incentives to engage in window dressing to bolster the level of leverage Tier 1 ratio at quarter-end. We also show that the persistency of window dressing is related to the computation of the Federal Deposit Insurance Corporation assessment base, which motivates banks to engage in window dressing to reduce the deposit insurance premium.

Piston driven yaw mechanism

2014

Masteroppgave i mekatronikk MAS 500 Universitetet i Agder 2014 The current thesis presents a piston driven yaw mechanism for wind turbines. Traditionally the yaw mechanismhas been one of the mayor contributors to down time and repair has been costly. The proposed designaims to improve the reliability of the yaw mechanism by reducing the point loads and by using hydrauliccylinders instead electrical motors to generate torque. In addition the design is modular allowing the mechanismto be disassembled and components to be replaced without the requirement of complicated or costlymachinery. The current thesis presents an analysis of the state of the art and discusses concepts which maysolve some…