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# NREL Phase IV wind turbine

The NREL Phase IV wind turbine has two blades with NREL S809 airfoil featuring non-linear twist and linear taper. The turbine radius is $$R=5.029$$m and the aspect ratio is $$AR=6$$. This case considers the turbine with a collective pitch of $$\theta=5$$deg, rotating at $$\omega=71.9$$rpm, at a freestream velocity of $$|\mathbf{V}\_{ref}|=7$$m/s. A structured mesh with 15 elements in the chordwise and 32 elements in the spanwise direction (for each blade) is used. The results are obtained with an azimuthal step of $$\Delta\theta=6$$deg ($$\Delta t=0.0139$$s) for 3 revolutions. The image below shows the pressure coefficient distribution.

![](/files/-Mh5F8jU-Pxe6Sf-WBcj)

The animation below shows the development of the wake.

{% embed url="<https://youtu.be/2BuFYhOvbjc>" %}
NREL Phase IV wind turbine wake development
{% endembed %}

The images below show the pressure coefficient at $$r/R=0.47$$. The experimental results from Hand et al. \[1] are shown for comparison.

<img src="/files/-Mh5M8S0DPfIcNN7Tvi7" alt="" data-size="original">&#x20;

## Files

{% file src="/files/-MgbQkB6x5Op\_Ml9Elai" %}

## References

\[1] Hand, M. and Simms, D., “Unsteady aerodynamic experiment phase VI: wind tunnel test configurations and available data campaigns,” NREL Technical Report TP-500-29955, 2001