5.3 VALIDATION OF SIMULATION WITH DATA PRESENT IN THE
LITERATURE
5.3.1 C
p
vs λ Curve
In this study, the validation of the simulation is done using the C
p
vs λ curve available in the
existing literature [71]. The Power coefficient is calculated as mentioned in the previous section
by averaging the moment coefficient and multiplying the average moment coefficient with the
tip speed ratio (TSR). Although the results show some discrepancy, the curve obtained by the
simulated results matches considerably with the experimental curve as shown in the figure:
Figure 23: Validation of the simulation with C
p
vs λ curve
5.4 VELOCITY FIELD PLOTS
The simplest and easiest assumption that can be made about the flow-field across a VAWT is to
consider uniform velocity of 10 m/s across the turbine. But in reality, this is not true as it can be
seen from the velocity contour in figure 24 and figure 25.
The magnitude of velocity starts to decrease as wind flows near the VAWT rotor. At the blades’
trailing edge, the magnitude of wind velocity remains the lowest. After striking the wind at the
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rotor blade, the wind also generates some angular velocity and hence begins to gain velocity
again.
Generally, at leading edges of the turbine blades, and mainly on the pressure sides of the blade,
regions of higher velocities are observed. The lowest velocities are usually observed at the back
side of the rotors, which always creates a vacuum.
Figure 24: Velocity contour plot
Figure 25: Velocity contour plot (zoomed)
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CHAPTER 6: CONCLUSIONS AND RECOMMENDATIONS
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