Figure 5. Comparison of contours of the dimensionless time-averaged (a, b) axial and (c, d) radial velocities between (a, c) LES predictions and (b, d) experimental results on the plane of P45.
To further evaluate the prediction accuracy, two radial positions on the plane of P45, i.e. r /R = 0.7 and 0.9, are taken out for quantitative comparison. The profiles of the dimensionless time-averaged velocities and velocity fluctuations (in terms of RMS velocities), are shown in Figures 6 and 7, respectively. Here, the time-averaged velocities and velocity fluctuations are all normalized by the tip velocity of the composite blade, U tip. Obviously, the predicted time-averaged radial and axial velocities are almost identical with the experimental results. However, there is a slight difference between the predictions and the experimental results for the velocity fluctuations, although the profile distribution patterns are very similar. The velocity fluctuations are over-predicted with a mean error of about 25%.