Blade Element Calculations - Small Wind Turbines: Analysis, Design, and Application - page 85

5.3 Running the Programs
Shown below is a typical run of tcdist.m and power_calc.m for comparison with
the measurements of Anderson et al. [ 5 ] for a 3 m diameter two-bladed turbine at
U 0 = 10 m/sec. Note that the programs are run in Matlab's command window and
that [[ is the prompt. The hub radius was taken as 0.133 m from Table 3.1 .
Fifteen blade elements were used. All blade element calculations have converged
as the number of iterations is always less than 41, and no angle of attack or
Reynolds number was out of range.
Figure 5.2 a shows the predicted and measured C P , and Fig. 5.2 b shows the
corresponding thrust coefficient. It must be noted that a was outside (higher than)
the tabulated range for some blade elements for k B 7 so those results must be
treated with caution. Some specific results for k = 8, 10, and 12 are shown in
Figs. 5.3 , 5.4 , 5.5 and 5.6 inclusive. Note that the torque and thrust contributions
from blade elements, given in the highlighted output below and plotted in Figs. 5.5
and 5.6 , sum to C Q = C P /k and C T respectively.