What's New To IECWind 5.0? Version 5.0 of the IECWind program has been updated to account for changes made to the IEC standard, IEC 61400-1 Edition 3. The input file has changed also, and hence input files for earlier versions are not compatible. Internal workings of the code have been updated to FORTRAN90. The output file name convention has changed and now are named with the prefix of the IEC condition listed in the input file followed by the suffix ".wnd" The conditions you wish to generate are now listed at the end of the input file. The convention for the names is provided in hte file InputDescription.txt. Any questions or comments regarding this code should be directed to: Dr. David J. Laino Windward Engineering, LLC email: dlaino@windwardengineering.com ___________________________________ What's New To IECWind 4.0? Version 4.0 of the IECWind program has been updated to account for changes made to the IEC standard, IEC 61400-1. The input file has changed also, and hence input files for earlier versions are not compatible. With the changes made to the standard, additional inputs are required - the turbine hub-height and rotor diameter. These have been added to the 11th and 12th lines of the input file. ___________________________________ What's New To IECWind 3.0? Version 3.0 of the IECWind program differs from version 2.0 only in the format of the output wind files. The new format has 8 columns, and include both a power law and linear vertical shear coefficient column in all files. This change makes the output wind files compatible with YawDyn version 11.0. Users of IECWind 2.0 will find 3.0 identical in all other aspects. If you use YawDyn version 10.0 (or earlier), you should use IECWind 2.0. If you are not already familiar with IECWind, or are only familiar with versions earlier than 2.0, read the section below to learn how to use this version, which differs greatly from earlier versions. ___________________________________ What's New To IECWind 2.0? Version 2.0 of the IECWind program is markedly different from previous versions of the program, and it is highly recommended that you read this brief file before using it. A major difference you will not notice until you examine the output of the program is that it uses the wind definitions from IEC 1400-1 edition 2, which are significantly changed from the previous edition. The changes made to the definitions include the separation of the vertical and horizontal wind shears in the Extreme Wind Shear (EWS) condition. Thus, there are now two options; instead of just EWS there are the EWSH (horizontal) and EWSV (vertical) options. A difference you will notice immediately is a change in the number and order of the inputs, as well as a change in the inputs themselves. Added to the input file is a wind turbulence category which is new in IEC 1400-1 edition 2. There are now two categories, A and B. A is the higher turbulence category. Details are provided in the standard. Two wind speeds can now be specified in the input file; both the rated and cut-out. This follows the IEC standard which allows definitions based on either wind speed for most conditions. The exceptions are ECG and ECD which use only rated wind speed. Thus, rated wind speed must be specified to generate these conditions. If either rated or cut-out are specified as 0.0 (or less), conditions will not be generated for that wind speed. One of these must be greater than zero, except when generating EWM conditions which do not require a hub-height wind speed to be specified. An inclination angle can now be specified between +8 and -8 degrees for the wind inflow. Horizontal and vertical hub-height wind speeds are resolved based on this angle. Note that the vertical component that is resolved in the wind file is considered to be the same across the entire rotor at any given time; that is, no shear is applied to this vertical component to change its value across the rotor. Missing from the new input file is an end time for the wind file. IECWind sets an end time of 10 minutes (600 seconds) which should be more than sufficient for all cases. The actual simulation time will be set in your simulation program input file. This change does not make the wind file any larger. All input lines should be present to run IECWind. However, meaningless entries or even blank lines can be used where that parameter is not needed by the program. IECWind will only return errors where a needed parameter is missing or in error. The ALL option now produces up to 25 files. It creates all conditions in both positive and negative wind and shear directions where appropriate, and for both rated and cut-out wind speed if both are specified. All conditions generated are for the specified wind turbine class, turbulence category, and wind inflow slope. The output wind file name convention is as follows: XXXX##XX.WND where, for the prefix: the first three letters are the IEC condition the fourth letter is H for horizontal or V for vertical shear for the EWS condition, _ for all other conditions the next two numbers are 50 or 01 for a 50 or 1 year recurrence rate, or 00 where no recurrence rate is applicable the second to last letter is P or N for positive or negative wind direction or shear, _ where no direction is applicable the last letter is R or O for rated or cut-out wind speed, _ for the EWM conditions for which neither wind speed is applicable Thus, ECG_00_R.WND is the Extreme Coherent Gust condition, which has no recurrence interval (hence 00), no wind direction or shear direction (hence the second _), and is only applicable to the rated wind speed (hence the R). Likewise, EWSH00NO.WND is for the negative Extreme Horizontal Wind Shear at cut-out wind speed, and EOG_01_R.WND is the 1 year recurrence Extreme Operating Gust at rated wind speed. Any questions or comments regarding this code should be directed to: Dr. David J. Laino Department of Mechanical Engineering University of Utah Salt Lake City, UT 84112 phone: 801.585.7405 fax: 801.585.9826 email: dlaino@stress.mech.utah.edu