Release v4.2.0

[andrew-platt]

Changelog (from 4.1.2)

---

Overview

This release contains improvements to the AeroAcoustics module in AeroDyn, an improved cubic interpolation in HydroDyn and SeaState, an improved teeter inertia model in ElastoDyn for 2 bladed turbines, and many other small improvements and bug fixes.

General

Build systems

CMake

#3163 AA driver: add driver compile to cmake (@andrew-platt)

Visual Studio (Windows)

#2922 Update Visual Studio compile settings for C Binding interfaces (@rafmudaf)

Documentation

#3015 Fix readthedocs copyright year, add link to docs when calling openfast help (@mayankchetan)

#3083 docs: update info on VS versions and IFX

#3109 Docs: updates to StC docs (@andrew-platt)

#3166 Update project description from NREL to NLR (@andrew-platt)

Solvers

FAST.Farm

#2952 FAST.Farm: skip writing invalid VTK slices (@andrew-platt)

#3031 FF: align initial wake grid with the blades (@andrew-platt)

#3104 FF WAT: change default WAT_Scalebox to True (@andrew-platt)

#3145 WD: Ct_avg was not set when polar wake used giving RtCtAvgT (@andrew-platt)

OpenFAST

#3009 Linearization: Fix pointer to dUdy block for SD inputs to MAP outputs (@bjonkman)

#3111 Add error message when using BeamDyn with AeroMap (@deslaughter)

#3146 Reenable writing check point files when using the MAP module (@deslaughter)

#3156 Linear Trim Solution: update range calculation when NLinTimes=1 (@bjonkman)

OpenFAST interfaces

OpenFAST library

#2965 FASTlib: missing error handling on FAST_CFD_WriteOutput (@andrew-platt)

#3064 FASTlib: fix typo in error message

c-bindings interfaces

#2974 Add registry file for AeroDyn_Inflow_C_Binding (@andrew-platt)

#2997 Updates to SeaState c-bindings library interface (@andrew-platt)

#3108 Updates to c-bindings (@andrew-platt)

Modules

Multiple

#2975 Minor numerical improvements (@bjonkman)

AeroDyn

AeroAcoustics

#2948 AeroAcoustics code cleanup (@bjonkman)

#3134 [BUG FIX] AeroAcoustics module angle range (@bjonkman)

#3133 [Bug Fix] Fix the element size calculation in AeroAcoustics module (@bjonkman)

#3144 [Bug Fix] Fix the element size calculation in AeroAcoustics module (@andrew-platt)

#3149 AeroAcoustics cleanup + added driver code (@bjonkman)

AWAE

#3025 [BugFix] FF awae: set v_plane=0 when center of wake plane leaves domain (@andrew-platt)

ElastoDyn

#2953 ED: Implemented the ability to add concentrated masses to the tower (@luwang00)

#2981 Allow separate teeter inertia for 2-bladed turbines (@abhineet-gupta)

HydroDyn

#2895 HD: Additional transverse drag modeling options for rectangular members (@luwang00)

#3076 Miscellaneous bug fixes for HydroDyn (@luwang00)

#3141 HD: Fixed a bug with PtfmRefztRot (@luwang00)

InflowWind

#3099 ifw flowfield: add box corners to out of bounds message on 4D (@andrew-platt)

MoorDyn

#2946 Changed submergence calculation and added additional rod outputs for input file MoorDyn (@KylerF229)

#2977 Minor MoorDyn improvements (@ryandavies)

#3034 MoorDyn: increase number of attachment points possible for bodies/anchors/points

NWTC-Library

#3148 NWTC Library: update error message with IOSTAT return value (@bjonkman)

SeaState

#3007 Cubic interpolation for SeaState and HydroDyn (@luwang00)

ServoDyn

#3158 SrvD: updates to StC control from DLL (@andrew-platt)

TurbSim

#3020 TurbSim: OpenMP parallelization in factorization and FFT

Wavetank

#3065 New wavetank library for HIL simulations with AD+MD (@andrew-platt)

Testing and input file processing

openfast_io

#2957 More MoorDyn Output Channels in openfast-io chans (@dzalkind)

#3001 prepping for py314 and making requirements less restrictrive (@gbarter)

#3130 Fix FAST_Reader bug when ElastoDyn tower file path is absolute (@louis-papillon)

#3153 FAST_reader.py fix for ServoDyn.dat GenTrq_TLU read (@LKa505)

GitHub actions

#3162 Fix simulink build for Windows in GH Actions (@andrew-platt)

Regression and Unit testing

#3159 Add in yaw friction cases (@andrew-platt)

#3173 Add aerodyn driver test for MHK turbine with IfW based inflow (@deslaughter)

Input file changes

Known issues

There are several issues that have not been addressed in this release due to time constraints, but will be addressed in future releases. These include:

• No visualization of rectangular members from HydroDyn or SubDyn through the VTK output options
• Missing and broken features from several c-binding library interfaces:
  • the AeroDyn_Inflow_c-binding library interface does not allow for coupling to the tower. This will require an interface update.
  • the HydroDyn_c-binding library interface does not currently support vizualization. This will require an interface update.
  • the InitNodePositions input to HydroDyn_c-binding library interface does not currently work with any non-zero x or y coordinates (non-zero z is ok)
  • the MoorDyn_c-binding library interface does not currently support vizualization. This will require an interface update.
• Documentation on the new pyOpenFAST module is incomplete. Partial documentation exists on how to use it in regression testing, but no documentation or examples exist on using it to call c-bindings modules from Python.
• Documentation is incomplete for HydroDyn, SubDyn, and a few other modules.

Precompiled Windows Binaries

The binary files in this release were built with the Visual Studio solution files distributed with OpenFAST (not using cmake), using

• Intel Fortran Essentials 2025.3.0.333
• Microsoft Visual Studio 2022 Version 17.14.23.
• MATLAB 2025.2.999 (R2025b)
• Executables with _OpenMP or _OMP in the name are built with OpenMP libraries and linked with dynamic libraries.
  • You will need this Intel Fortran redistributable package installed to use these executables if you do not already have Intel Fortran OneAPI 2024 installed. See the installation instructions here.

---

This discussion was created from the release Release v4.2.0.