A 3D wake numerical simulation method based on 2D_k Jensen model

Abstract

The invention provides a three-dimensional wake numerical simulation method based on a 2D_k Jensen model, which can obtain a novel three-dimensional wake model. The method is characterized in that: step 1, calculating an inflow wind shear curve u0 (z) and the turbulence intensity distribution I0 (z) in the vertical direction; 2, calculating that expansion coefficients kx, z of the wake; 3, predicting that wake wind speed based on the original Jensen model to obtain the initial wake wind speed u* (x, z); 4, calculating that expansion radius rx, r of the wake; 5, utilizing that wake expansion radius rx, r obtained in the step 4, based on the cosine-type velocity distribution proposed by the 2D_kJensen model, three-dimensionally modifying the initial wake wind speed u* (x, z) obtained in thestep 3 to obtain the corrected wake wind speed distribution u (x, y, z). The three-dimensional wake model obtained by the invention inherits the advantages of the engineering model, and has good prediction accuracy for the wake velocity deficit in the direction of flow direction, the cross wind direction and the vertical direction, and can effectively reflect the asymmetric characteristics of thevelocity deficit in the vertical direction, and the calculation accuracy is even better than the numerical simulation result based on the CFD method.

Description

technical field [0001] The invention belongs to the technical field of wind power generation. Background technique [0002] The wake effect of the wind turbine will cause the downstream wind speed to decrease, the turbulence intensity to increase, and the wind shear to increase. The reduction of wind speed reduces the output power of the downstream unit, and the strong turbulence and additional wind shear will also affect the fatigue load, structural performance and service life of the downstream unit. For a wind farm with a limited scale, the wind turbines in it will inevitably operate in the wake of the surrounding units, and the wake effect becomes an important factor that should be considered in the arrangement and optimization of wind farm units. Due to the need to continuously evaluate the impact of arrangement and installation spacing changes in the process of unit layout optimization, it is impossible to achieve this through computational fluid dynamics (CFD) numeri...

AI Technical Summary

Problems solved by technology

However, according to research, one-dimensional wake models are commonly used at home and abroad, a few use two-dimensional models, and there are almost no corresponding three-dimensional wake models for reference and use.

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