A specific feature of wind power generation is the stochastic behavior of wind velocity what determines the energy produced, and also influences the turbine degradation process due to the stochastic load suffered by the wind turbine. Thus, wind turbines present a degradation process more complex than the equipment that work under stationary conditions.The selection of maintenance strategy, that...

Asymptotically exact and nonlocal third order nonlinear evolution equations are derivedfor two counterpropagating surface capillary gravity wave packets in deep water in thepresence of wind flowing over water.From these evolution equations stability analysis ismade for a uniform standing surface capillary gravity wave trains for longitudinal perturbation. Instability condition is obtained and g...

We use the Cluster EFW experiment to measure the cross-shock electric field at ten low β, quasi-perpendicular supercritical bow shock crossings on March 31, 2001. The electric field data are Lorentz-tranformed to a Normal Incidence frame (NIF), in which the incoming solar wind velocity is aligned with the shock normal. In a boundary normal coordinate system, the cross-shock (normal) electric fi...

The contribution of this paper is the formulation of the wind farm power maximization problem as a multi-stage dynamic programming problem. This formulation is made possible by introducing a state-space model to describe the evolution of the wind velocity profile as a function of the free-stream wind velocity and the wind turbine control variables. This state-space model is coupled with a multi...

Abstract. Doppler sonar observations of surface velocity are analysed to extract an rms velocity scale related to flow patterns persisting for at least a minute, and having advection velocities within an adjustable "window" of the mean advection rate. The resulting velocity scale is related to the wind and waves over the course of the twenty days available from the SWAPP data set. The correlati...

Context. Thermal wind emission in the form of free-free and free-bound emission is known to show up in the infrared and radio continuum of hot and massive stars. For OB supergiants with moderate mass loss rates and a wind velocity distribution with β ≃ 0.8 . . . 1.0, no influence of the wind to the optical continuum, i.e. for λ <∼ 1.0 μm, is expected. Investigations of stellar and wind paramete...

The 3-D structure of the solar wind varies dramatically along the Sun’s activity cycle. In the present paper we focus on some properties of the polar solar wind. This is a fast, teneous, and steady flow (as compared to low-latitude conditions) that fills the high-latitude heliosphere at low solar activity. The polar wind has been extensively investigated by Ulysses, the first spacecraft to perf...

the technique used to control the airflow is based on the electro-hydrodynamic actuator which is also called plasma actuator. this actuator ensures the airflow control thanks to the electric wind created by the electrical corona discharge. this ionic wind is developed at the profile surface tangential to the initial free airflow so that it has a significant effect on the boundary layer flow. th...

[1] This study provides a fast and easy‐to‐apply method to estimate threshold friction velocity (TFV) of wind erosion in the field. Wind tunnel experiments and a variety of ground measurements including air gun, pocket penetrometer, torvane, and roughness chain were conducted in Moab, Utah and cross‐validated in the Mojave Desert, California. Patterns between TFV and ground measurements were ex...

The aerodynamic admittance function (AAF) has been widely invoked to relate wind pressures on building surfaces to the oncoming wind velocity. In current practice, strip and quasi-steady theories are generally employed in formulating wind effects in the along-wind direction. These theories permit the representation of the wind pressures on building surfaces in terms of the oncoming wind velocit...