Influence of Low-Level Jet intensity on aerodynamic loads of horizontal axis wind turbine rotor

Abstract

High wind speeds associated with Low-Level Jet (LLJ) make wind resources more favorable for wind energy production. However, the aerodynamic loads of large-scale horizontal axis wind turbine (HAWT) rotor under different LLJ inflow conditions have not been thoroughly studied. To gain insight into the aerodynamic loads of rotor under LLJ inflow conditions with different LLJ intensities, a method to establish an engineering LLJ inflow model was proposed according to the plane wall jet theory and Von Karman spectra model with user-defined scaling. The parameters in the engineering LLJ inflow model were determined by comparing the wind speed distribution obtained from the GP_LLJ spectral model, which was summarized from field measurements in the real atmosphere. The LLJ fluctuating wind fields with different intensities generated by the engineering LLJ inflow model were used as the inflow conditions of Fatigue, Aerodynamics, Structures, and Turbulence (FAST) open source code to calculate and analyze the aerodynamic loads of the HAWT. It was found that the engineering LLJ inflow model can be used to establish the LLJ inflow condition of HAWT. When the LLJ height is located at the hub height and LLJ intensity increases from 8 to 16 m/s, the RMS rotor unbalanced aerodynamic load coefficients, including ones of lateral force, longitudinal force, tilt moment and yaw moment are increased by 2.2, 2.13, 1.02 and 0.95 times, respectively. ARTICLE HISTORY

Study on the Influence of Low-Level Jet on the Aerodynamic Characteristics of Horizontal Axis Wind Turbine Rotor Based on the Aerodynamics–Controller Interaction Method

“…The LLJ-based models are usually summarized using observed data, but the data are regional; therefore, an engineering-based model is adopted in the present work [8], and the LLJ is regarded as a superposition of the WS and free jet, which is expressed as follows:…”

“…Na et al [7] explored the flow field characteristics of wind turbines in the presence of the LLJ conditions by the large-eddy simulation method. Among them, the influence of the LLJ on the aerodynamic characteristics of the wind rotor is the most noticeable with the increase in the hub height [8,9]. When the LLJ occurs, the inflow condition becomes very complicated, characterized by strong winds at the height of the LLJ and strong wind shear.…”

Three-dimensional fluid-solid coupling heat transfer simulation based on the multireference frame for a side-blown aluminum annealing furnace

“…In addition, the calculation of the turbulent dissipation rate is also different from the standard k-model. At present, the model has been widely used to calculate more complicated flow conditions such as a swirling shear flow, a planar mixed flow (Bridgeman, Jefferson, & Parsons, 2009), a jet (Li, Wang, & Chen, 2018;Zhang, Yang, & Li, 2019), and so on:…”

Occurrence of Low-Level Jets over the Eastern U.S. Coastal Zone at Heights Relevant to Wind Energy

“…However, it is also likely to be associated with enhanced static and mechanical loading, fatigue cycles and deflections [30]. A study using the NREL FAST code to model interaction of a LLJ with a horizontal-axis wind turbine found increased power and aerodynamic loads in the presence of positive and negative shear regions of the LLJ [31].…”