A simple mode-shape generator for both towers and rotating blades.

by Marshall Buhl
supported by Jason Jonkman
National Wind Technology Center

Modes generates mode shapes for towers and blades. The blades can rotate at a user-specified rate, which can also be set to zero for non-rotating blades.  The beams are divided into rigid and flexible sections. The user specifies basic information on geometry, plus mass and stiffness distributions.  This information is stored in a small input file.

Modes is primarily intended to be used with FAST, but you may find other uses for it.


Modes was a program that was originally created by Dr. Robert Wilson and his colleagues at Oregon State University. They used it to create the mode shapes that their FAST program needed for flexible blades and towers. While verifying FAST against other codes, Marshall used Garrad Hassan's GH BLADED to generate mode shapes. As the time approached to release the newly debugged version of FAST, he realized we needed something we could distribute with it for generating its mode shapes. Marshall got a copy of Modes, modernized it, and made some improvements.

You may download the following file from our server:

  • Modes Change Log (v2.22, 2 KB, 29-April-2002)

    This is the Modes change log.  Look at this text file to see if we've made worthwhile changes since you received your previous version of RunIEC.

  • Modes Read-Me File (v2.2, 9 KB, 05-April-2001)

    This is plain text file that explains what Modes does and how you can use it.

  • Modes Archive (v2.22, 320 KB, 29-April-2002)

    This is a self-extracting archive of Modes for PCs.  It includes the Modes executable program, the source code, the change log, the read-me file, and sample input and output files.

Programming Language:     Wind and Water Tools:

You must log in to download this software.

If you want to refer to this website in a report, here is a reference you can use:
NWTC Information Portal (Modes). Last modified 28-September-2014 ; Accessed 23-February-2017