- 上一篇：轧钢机英文文献和中文翻译
- 下一篇：钢筋混凝土桥梁英文文献和中文翻译
4 Results
结果
One of the parameters which characterize VAWTs is the Tip Speed Ratio (TSR) which represents the ratio of the airfoil tip speed Uϕ and the undisturbed wind velocity Uw
For the rotor geometry and wind velocity given in the Table 1, results presented in thefollowing subsections are referenced to λ.
特征VAWTs参数之一是提示速度比（TSR）的代表的翼型件的末梢速度Uφ的比率及原状风速Uw的用于转子的几何形状和在表1中给定的风速，结果列于以下各小节引用λ。
4.1 Two Dimensional Rotor Approximation
4.1二文转子逼近
The appropriate two dimensional (2D) CFD model is sketched in Figure 3. Thesolution domain consist of two sub-domains: the inner rotating part and the outer stationar part. The numerical schemes solve the three dimensional RANS equations.T us, symmetry boundary conditions are imposed at the top and bottom face of thecomputational domain consisting of one layer of prismatic and hexagonal cells. At theleft face, a constant velocity inflow is imposed and at the right side outflow boundaryconditions are imposed. At the airfoil, appropriate boundary conditions depending onthe turbulence model with scalable wall functions are imposed.
适当的二文（2D）CFD模型被描绘在图3。 “解域包括两个子域：内层旋转部分和的外stationar部的。数值格式解决了三文RANS方程。ţ我们，对称边界条件强加在顶部和底部的面的计算域的棱柱形和优尔角形细胞组成的一层。在左边的脸，以恒定的速度流入罚款，并在右侧流出的边界条件罚款。在翼型件，适当的边界条件下，取决于湍流模型与可伸缩的墙功能的罚款。
The efficiency of the turbine is expressed by the power coefficient
where P is the average power of the turbine, ρ is density of the undisturbed wind and a is the vertical cross-section area of the rotor. Figure 4 shows a comparison of the DMST model and the CFD predictions. A quite good agreement of CP is observed for λ < 2 (Figure 4a). Large deviations for larger values of λ may be explained with the dynamic stall effect which is not included in the present model. This is obvious from Figure 4b where the normalized moment of the single airfoil is compared. For the rotor position in the vicinity of ϕ = 0◦, CFD predicts significantly higher negativemoment. This may be not explained with the inappropriate aerodynamic coefficients. The angle of attack is significantly below the static stall angle where the sensitivity of the aerodynamic coefficients with respect to the Reynolds number is quiet low. The only explanation may be found in the dynamical change of the angle of attack and the dependence of the aerodynamic coefficients on it.
其中，P是在涡轮机的平均功率，ρ为密度的不受干扰的风，并且a是所述转子的垂直横截面面积。图4示出了比较的DMST的模型和CFD预测。一个相当不错的CP达成的协议是观察到的λ<2（图4a）。可以解释，不包含在本模型的动态失速效应较大的λ值的大偏差。这是显而易见的，从图4b中的单个翼型的归一时刻比较。对于转子的位置附近的φ= 0◦，CFD预测显著更高的negativemoment。这可能不被解释与不合适内容的空气动力系数。迎角是显着低于静态失速角的灵敏度相对于雷诺数的空气动力系数是安静的低。唯一的解释中可以找到的动态变化的角度的攻击和其上的空气动力系数的依赖性。
The above presented results clearly shows that the dynamic change of the angle of attack must be included in the DMST model. This effect is investigated using the CFD simulations presented in the following subsection.
上面给出的结果清楚地表明，该动态变化的角度的攻击必须包含在DMST模型。这种效果是使用CFD调查模拟在以下的小节。