Rotational sampling in wind turbines: Difference between revisions

Revision as of 23:00, 13 June 2023

Latest revision as of 18:06, 21 June 2023

(2 intermediate revisions by 2 users not shown)

Line 1:

{{Further|Wind turbine design}}

{{Issues|

{{RefimproveMore citations needed|date=October 2013}}

The loads on both [[horizontal-axis wind turbine]]s (HAWTs) and [[vertical-axis wind turbine]]s (VAWTs) are [[cyclic]]; the [[thrust]] and [[torque]] acting on the blades depend on where the blade is. In a horizontal axis wind turbine, both the apparent [[wind speed]] seen by the blade and the [[angle of attack]] depends on the blade's position. This phenomenon is described as [[Rotational sampling in wind turbines|'''rotational sampling]]'''. This article will provide insight into the cyclic nature of the loads that arise because of rotational sampling for a horizontal axis wind turbine.

}}

The loads on both [[horizontal-axis wind turbine]]s (HAWTs) and [[vertical-axis wind turbine]]s (VAWTs) are [[cyclic]]; the [[thrust]] and [[torque]] acting on the blades depend on where the blade is. In a horizontal axis wind turbine, both the apparent [[wind speed]] seen by the blade and the [[angle of attack]] depends on the blade's position. This phenomenon is described as [[Rotational sampling in wind turbines|rotational sampling]]. This article will provide insight into the cyclic nature of the loads that arise because of rotational sampling for a horizontal axis wind turbine.

Rotational sampling can be divided into two parts: [[Deterministic system|deterministic]] and [[Stochastic process|stochastic]]. Deterministic processes present themselves as spikes on a [[Power spectral density|power spectrum]], where as stochastic processes spread over a wider [[frequency range]].

{{Further|Wind turbine design}}

==Background==

Line 18 ⟶ 15:

* Tower shadow <ref>Time-Domain Modeling of Tower Shadow and Wind Shear in Wind Turbines,

Swagata Das, Neeraj Karnik, and Surya Santoso</ref>

* [[Wind shear]] <ref>Time-Domain Modeling of Tower Shadow and Wind Shear in Wind Turbines,

Swagata Das, Neeraj Karnik, and Surya Santoso</ref>

Line 64 ⟶ 61:

</math>

The [[covariance]] function of a sum of [[Sinusoidal model|sinusoids]] is itself a sum of [[Sinusoidalsinusoidal function|sinusoidal functions]]s. Thus, the power spectral density function is a set of Dirac delta functions. The locations of these are at multiples of ''n''. Thus, on a power spectrum, deterministic processes such as gravitational loading manifest themselves as spikes. This can be seen from analysing generator torque.

====Blades====

Line 70 ⟶ 67:

==Structural loads==

[[Spectral analysis (disambiguation)|Spectral analysis]] of component loading is useful in [[fatigue analysis]].

==References==

{{Reflist}}

[[Category:Wind turbines]]

{{Improve categories|date=June 2023}}

[[Category:Wind turbines]]