I have uploaded a new version of TurbSim (v1.30) to the NWTC Design Codes web site. You can download it at http://wind.nrel.gov/designcodes/preprocessors/turbsim/.

Version 1.30 contains two new inputs to the input file. The first is a true/false switch that allows the user to scale the output of the IEC Kaimal and von Karman models to the exact specified turbulence intensity (TI) at the hub point. The second new input is the “c” parameter in the equation for extreme turbulence (section 6.3.2.3 of IEC 61400-1 Ed 3). I added a couple of paragraphs to the user’s guide to explain these inputs.

I’ve modified the summary file a little bit, too. What the summary file previously called “longitudinal” was actually the wind component in the X direction of the inertial frame. The summary file now prints stats for both reference frames: aligned with the mean flow, and the inertial reference frame. Everything in the inertial reference frame now has upper-case letters and everything defined in the reference frame aligned with the mean flow uses lower-case letters. I’ve also modified the TI calculation in the summary file to be the component standard deviation divided by the mean longitudinal wind speed. TurbSim was previously using the mean total wind speed for these calculations, which would produce smaller TI.