Last code update: Jan 15, 2016
The Wake Induced Dynamics Simulator (WInDS) is a lifting-line theory (LLT) based free vortex wake method (FVM) code developed at the University of Massachusetts Amherst Wind Energy Center with the express purpose of modeling the offshore floating wind turbine (OFWT) aerodynamics to a higher degree of accuracy than is possible via momentum balance methods. WInDS natively incorporates the multiple DOFs present in offshore floating wind turbines, resulting in a more realistic simulation of the flow field. Examples of wake simulations available at https://www.youtube.com/user/tommysebastian314159
WInDS was originally developed by Tommy Sebastion at the University of Massachusetts Amherst in 2011 and has been modified, through ongoing work, to the present. This document is meant to provide a basic description of the WInDS code, and to provide the source code and supporting files for other users.
PLEASE NOTE: WInDS is not supported by University of Massachusetts Amherst Wind Energy Center or any of its associated staff or researchers. No formal user support or requested modifications will be provided. Emailed questions will be responded to on an ad-hoc basis.
Description of the Code
Several early publications describe the theoretical background and practical implementation for WInDS, most notably the doctoral dissertation of Thommy Sebastian. The original version of WInDS described in these publications is available on the MathWorks File Exchange. Details are available in these earlier publications:
- Sebastian T., "The Aerodynamics and Near Wake of an Offshore Floating Horizontal Axis Wind Turbine." Doctoral Dissertation. 2012. Available at http://scholarworks.umass.edu/open_access_dissertations/516/
- Sebastian T., Lackner M.A., “Characterization of the Unsteady Aerodynamics of Offshore Floating Wind Turbines.”Wind Energy, Available online: DOI: 10.1002/we.545, 2012.
- Sebastian T., Lackner M.A., “Development of a Free Vortex Code for Offshore Floating Wind Turbines.” Renewable Energy, Available online: DOI: 10.1016/j.renene.2012.03.033, 2012.
- Sebastian T., Lackner M.A., “Analysis of the Induction and Wake Evolution of an Offshore Floating Wind Turbine.”Energies: Special Issue on Wind Energy, Vol. 5, No. 4: 968-1000 2012.
The latest version of the WInDS code is provided on this site. It includes signifcant modifications, such as parrallel processing of the Biot Savart law on GPUs and the inclusion of a Leishman-Beddoes dynamic stall model. Details are available in:
- deVelder N., "Free Wake Potential Flow Vortex Wind Turbine Modeling: Advances in Parrallel Processing and Integration of Ground Effects." Masters Thesis. 2014. Available at http://scholarworks.umass.edu/theses/1176/
- Gaertner E., "Modeling Dynamic Stall for a Free Vortex Wake Model of a Floating Offshore Winds Turbine." Masters Thesis. 2014. Available at http://scholarworks.umass.edu/masters_theses_2/85/
- Gaertner E., Lackner M.A., "Modeling Dynamic Stall for a Free Vortex Wake Model." Wind Engineering, Vol. 39, No. 6, 2015.
Please feel free to refer to any and all of these publications.
The WInDS source files are included in "winds.zip" below.
- WInDS is executed using the Matlab file "WInDS.m". This requires the user to own a valid Matlab license, with expected compatability for Matlab 7.5 (R2007b) and higher.
- User inputs and model settings are controlled in "WInDS.m". Run time model initialization and the main time marching loop are also found in this file.
- Users can run parameter studies using the file "pWInDS.m". This file allows users to change multiple inputs to form a test matrix of WInDS simulations which will be run in series.
A user manual is provided in the winds.zip folder, which provides a theoretical overview and describes the wide range of function and variables included in the WInDS code. This should serve as an adequate primer for new users to begin using the model. However, it should be noted that the manual is no longer up to date with the current version of WInDS. A notable example is the transition from 4D to 6D arrays ([cartesian coordinates, time index, trailed nodes, shed nodes, blade number, rotor number]) to allow for analysis on multiple turbine rotors. Updated documentation is planned, but may not be available for some time.