Ashes wind turbine simulation
Superpowers to engineers!

1. Validation & benchmarks

1.1 Latest reports

1.2 Analytical tests

1.2.1 Structural tests

1.2.1.1 Decay test tower

1.2.1.2 Spring test

1.2.1.3 Nonlinear spring test

1.2.1.4 Nonlinear rotational spring test

1.2.1.5 Static pull: one-element model

1.2.1.6 Element weight

1.2.1.7 Blade structural offsets

1.2.1.8 Timoshenko Blade

1.2.1.9 Blade decay test

1.2.1.10 Blade rotational inertia

1.2.1.11 Fatigue test

1.2.1.12 Blade shear center offset

1.2.1.13 Eigenfrequency circular cylinder

1.2.1.14 Maximum stress

1.2.2 Unit tests

1.2.2.1 Euler-Bernoulli element with shear/mass center offsets

1.2.3 Environmental conditions

1.2.3.1 IEC extreme winds

1.2.4 Control system

1.2.4.1 Emergency stop

1.2.5 Aerodynamics

1.2.5.1 Cylindrical blade

1.2.5.2 One airfoil blade fixed

1.2.5.3 One airfoil blade

1.2.5.4 Aerodynamical reference point eccentricity

1.2.5.5 Tower shadow potential flow

1.2.5.6 Tower shadow Powles model

1.2.5.7 BEM - velocity triangle video

1.2.6 Hydrodynamics

1.2.6.1 Wave kinematics test

1.2.6.2 Morison test

1.2.6.3 Buoyancy test

1.2.6.4 Heave plate test

1.3 Benchmarking tests

1.3.1 Benchmark from Bell (1987)

1.3.1.1 Cantilever beam

1.3.1.2 Cantilever beam with two simple supports

1.3.2 Benchmark from Irgens (1985)

1.3.3 Benchmark from MacNeal (1985)

1.3.3.1 Curved beam

1.3.3.2 Straight beam

1.3.3.3 Twisted beam

1.3.4 DTU 10-MW Benchmarks

1.3.4.1 DTU 10-MW steady state performance

1.3.4.2 DTU 10-MW steady state performance, stiff blades

1.3.4.3 DTU 10-MW blade eigenfrequencies

1.3.4.4 DTU 10-MW steady state performance, Timoshenko blades

1.3.4.5 DTU 10-MW steady state performance, Timoshenko blades and rotational inertia

1.3.4.6 DTU 10-MW steady state performance, Timoshenko blades and offsets

1.3.4.7 DTU 10-MW whole turbine eigenfrequencies

1.3.5 OC3 Benchmarks

1.3.5.1 OC3 Phase I

1.3.5.2 OC3 Phase I load case 1.2

1.3.5.3 OC3 Phase II

1.3.5.4 OC3 Phase II load case 1.2

1.3.6 OC4 Benchmarks

1.3.6.1 OC4 Phase I load case 1.0b

1.3.6.2 OC4 Phase II

1.3.7 OC6 Benchmarks

1.3.7.1 OC6 Phase I

1.3.8 IEA 15-MW Benchmarks

1.3.8.1 IEA 15-MW steady state performance

1.3.8.2 IEA 15-MW blade eigenfrequencies

1.3.8.3 IEA 15-MW monopile weight

1.3.8.4 IEA 15-MW tubular tower weight

1.3.8.5 IEA 15-MW bladeless eigenfrquencies

1.3.9 NREL 5-MW Benchmarks

1.3.9.1 NREL 5-MW eigenfrequencies

1.3.10 MacCamy-Fuchs test

1.3.11 Dynamic stall test

1.3.12 Stream function test

1.3.12.1 Peeringa benchmark

1.3.12.2 Fenton benchmark

1.3.13 Morison total load

1.3.14 Vertical Axis Wind Turbines

1.3.14.1 De Tavernier (2022)

1.3.15 Potential flow wave excitation loads

2. Theory Manual

2.1 Nomenclature

2.1.1.1 BDB - Blade database

2.1.1.2 CM - Center of mass

2.1.1.3 CP - Power coefficient

2.1.1.4 DLC - Design Load Case

2.1.1.5 FEM - Finite element method

2.1.1.6 LAT - Lowest astronomical tide

2.1.1.7 MSL - Mean Sea Level

2.1.1.8 PID - Proportional-integral-derivative

2.1.1.9 RNA - Rotor-nacelle assembly

2.1.1.10 SSL - Standard sea-level conditions

2.1.1.11 SWL - Still water level

2.1.1.12 TM - Theory manual

2.1.1.13 UM - User manual

2.1.1.14 VSPR - Variable-speed pitch-regulated

2.1.1.15 WT - Wind turbine

2.1.2 Terminology

2.1.2.1 Aerodynamical reference point

2.1.2.2 Angle of attack

2.1.2.3 Aspect ratio

2.1.2.4 Blade aerodynamical station

2.1.2.5 Blade length

2.1.2.6 Blade reference line

2.1.2.7 Blade shape

2.1.2.8 Chord length

2.1.2.9 Chordline midpoint

2.1.2.10 Fields

2.1.2.11 In-plane

2.1.2.12 Influence length

2.1.2.13 Load case

2.1.2.14 Load case set

2.1.2.15 Out-of-plane

2.1.2.16 Parameter tag

2.1.2.18 Pitch axis

2.1.2.19 Scalar

2.1.2.20 Sensor

2.1.2.21 Time simulation job

2.1.2.22.1 Blade shape twist

2.1.2.22.2 Blade structure twist

2.1.2.22.3 Frame element twist

2.1.2.23 Wind angle

2.1.3 List of symbols

2.1.4 Abbreviations

2.2 Aerodynamics

2.2.1.1 Wind profile power law

2.2.1.2 Weibull distribution

2.2.1.3 Turbulence

2.2.1.4 IEC extreme events

2.2.1.5 Stepwise Wind

2.2.1.6 Linear wind

2.2.2 Aerodynamic loads

2.2.2.1 BEM algorithm

2.2.2.1.1 Steady BEM

2.2.2.1.2 Unsteady BEM

2.2.2.1.3 Glauert correction

2.2.2.2 DMST algorithm

2.2.2.3 Aerodynamic Loads on Support section elements - Aero drag loads

2.2.2.4 Aerodynamic Loads on Nacelle and Hub

2.2.2.5 Viterna extrapolation

2.2.2.6 Tower shadow models

2.2.2.6.1 Potential flow tower shadow model

2.2.2.6.2 Powles tower shadow model

2.2.2.7 Interpolation of aerodynamic coefficients

2.3 Oceanography

2.3.1 Water particle kinematics

2.3.1.1 Regular waves

2.3.1.2 Irregular waves

2.3.1.3 Stream function waves

2.3.1.4 Currents

2.3.2 Wave loads

2.3.2.1 Morison equation

2.3.2.2 MacCamy-Fuchs

2.3.2.3 Potential flow theory

2.3.4 Wave spectrum input file

2.4 Structural modeling

2.4.1 Catenary lines

2.4.2.1 Time domain simulation

2.4.2.1.1 Linear analysis

2.4.2.1.2 Damping

2.4.2.1.2.1 How to use Rayleigh damping

2.4.2.1.3 Stresses and responses

2.5 Geotechnical modeling

2.5.1 Soil stiffness

2.5.2 Linear springs

2.5.3 Damping - dashpots

2.5.4 Nonlinear springs

2.5.5 Hysteresis

2.6 Control theory

2.6.1 Variable speed generator

2.7 Fatigue analysis

2.7.1 Fatigure analysis procedure

2.7.2 Eurocode1993 S-N curves

3.1 First steps with Ashes

3.1.1 Downloading and installing

3.1.2 Computer requirements

3.1.3 Logging in

3.1.4 Starting window

3.1.5 Simulation window

3.1.6 Video Tutorials

3.1.7 Your user account

3.1.8 Release notes

3.1.8.1 Ashes 3.20

3.1.8.2 Ashes 3.19

3.1.8.3 Ashes 3.18

3.1.8.4 Ashes 3.17

3.1.8.5 Ashes 3.16

3.1.8.6 Ashes 3.15

3.1.8.7 Ashes 3.14

3.1.8.8 Older versions

3.1.9 Network installation guide

3.2 Designing your wind turbine

3.2.1 File formats

3.2.1.1 Airfoil geometry file

3.2.1.2 Airfoil polar file

3.2.1.3 Blade shape file

3.2.1.4 Blade structure file

3.2.1.5 Currents file

3.2.1.6 Load history file

3.2.1.7 Stepwise wind file

3.2.1.8 Support section files

3.2.1.8.1 Keywords

3.2.1.8.2 Support section examples

3.2.1.9 Wave spectrum file

3.2.2 Coordinate systems

3.2.3 Reference models

3.2.3.1 NREL 5-MW

3.2.3.2 DTU 10-MW

3.2.3.3 IEA 15-MW

3.2.3.4 IEA 22-MW

3.2.3.5 Hawc2 to Ashes

3.2.3.6 Mass and stiffness matrices to Ashes format

3.2.4 Create a custom rated power turbine

3.2.5 OpenFAST input into Ashes

3.2.6 Create a custom controller

3.2.7 Published models

3.3.1 Environment

3.3.1.1 Atmosphere

3.3.1.1.1 Live wind

3.3.1.1.2 Uniform wind

3.3.1.1.3 IEC extreme wind

3.3.1.1.4 Sine wind

3.3.1.1.5 Linear wind

3.3.1.1.6 Stepwise wind

3.3.1.1.7 Turbulent wind

3.3.1.3.1 Live wave

3.3.1.3.2 Regular wave

3.3.1.3.3 Irregular waves-single spectrum

3.3.1.3.4 Irregular waves-double spectrum

3.3.1.3.5 Currents

3.3.1.3.6 Stream function waves

3.3.2 Wind turbine

3.3.2.1.1 Rotor

3.3.2.1.1.1 Hub

3.3.2.1.1.1.1 Blade connection

3.3.2.1.1.2 Blades

3.3.2.1.1.3 Pitch actuators

3.3.2.1.2 Main shaft

3.3.2.1.3 Nacelle frame

3.3.2.1.4 Demanded pitch

3.3.2.1.4.1 Fixed

3.3.2.1.4.2 PID controller

3.3.2.1.4.3 Live

3.3.2.1.4.4 Bladed DLL

3.3.2.1.4.5 Python script

3.3.2.1.5 Generator

3.3.2.1.5.1 None

3.3.2.1.5.2 Variable speed

3.3.2.1.5.3 Induction

3.3.2.1.5.4 PMSG radial

3.3.2.1.5.5 PID controller

3.3.2.1.5.6 Live

3.3.2.1.5.7 Bladed DLL

3.3.2.1.5.8 Python script

3.3.2.1.6 Gearbox

3.3.2.1.7 Yaw actuator

3.3.2.1.7.1 Fixed

3.3.2.1.7.2 PID controller

3.3.2.1.7.3 Python script

3.3.2.2 Support structure

3.3.2.2.1 Tubular tower

3.3.2.2.2 Truss tower

3.3.2.2.3 Monopile

3.3.2.2.4 Floater - Semi-submersible

3.3.2.2.5 Floater - Spar buoy

3.3.2.2.6 Mooring system

3.3.2.2.6.1 Mooring lines

3.3.2.3 FEM Parts

3.3.2.4 Python script controller

3.4.1 Adding a sensor

3.4.2 Sensor list

3.4.2.1 Beam element sensor

3.4.2.2 Blade [Span] sensor

3.4.2.3 Blade [Time] sensor

3.4.2.4 Blade aerodynamical station sensor

3.4.2.5 Bladed DLL [Swap array] sensor

3.4.2.6 Demanded pitch sensor

3.4.2.7 Fatigue sensor

3.4.2.8 Floater motion sensor

3.4.2.9 Fluid kinematics sensor

3.4.2.10 Generator sensor

3.4.2.11 Generator [electrical] sensor

3.4.2.12 Individual load sensor

3.4.2.13 Loads on node sensor

3.4.2.14 Mooring line sensor

3.4.2.15 Node sensor

3.4.2.16 Pitch actuator sensor

3.4.2.17 Performance sensor

3.4.2.18 Rotor sensor

3.4.2.19 Rotor [Aero] sensor

3.4.2.20 Sea sensor

3.4.2.21 Solver sensor

3.4.2.22 Support sensor

3.4.2.23 Total hydro loads sensor

3.4.2.24 Total loads sensor

3.4.2.25 ULS sensor

3.4.2.26 Wind sensor

3.4.3 Customise sensor fields

3.4.4 Export the data

3.4.5 Velocity triangle

3.4.6 Visualize the data

3.5 Preferences

3.6 Simulations and analyses

3.6.1 Analysis parameters

3.6.1.1 Analysis

3.6.1.2 Initial conditions

3.6.1.3 Aerodynamics

3.6.1.4 Hydrodynamics

3.6.2 Static analysis

3.6.3 Eigenmodes

3.6.4 Rotor characteristics

3.6.6 Model Information

3.6.7 Using the command-line interface (ashes-cli)

3.7 Display settings

3.8 Batch manager

3.8.1 Batch window

3.8.2 Cloud computing

3.8.3 DLC generator

3.9 Turbulent Wind Creator

3.9.1 Turbulent wind tool

3.9.2 Mann turbulence generator

3.10.1 Blade database

3.10.2 Airfoil database

3.10.3 RNA database

3.11 Cloud functionalities

3.11.1 Cloud storage

3.11.2 Cloud sharing

3.11.3 Cloud computing

3.12 Python API in Ashes

3.12.1 Creating a Python Controller

3.12.2 Routing a Simulink and Labview Controllers through Python

3.12.3 Filtering out unnecessary data

3.12.4 Debugging the controller

3.13 Debugging your simulations

3.13.1 Crash report

3.13.1.1 Debug log file

3.13.1.2 Actions log file

3.13.1.3 Minidump file

3.13.1.4 Ashes project

3.13.2 Debugging the controller

3.13.3 Error messages

3.13.3.1 Displacement and load residual tolerances were not reached

3.13.3.2 The hub must be higher than half of the turbulent wind field height

3.13.3.3 Ill-conditioned or non-invertible system

3.13.3.4 Duplicated blades

3.13.3.5 One or more parts of the model have errors

3.13.3.6 A rotor moved outside of the boundary of the turbulent wind field

3.13.3.7 The turbulent wind file was not found

3.13.3.8 The spring had a displacement outside the range provided

3.13.3.9 The solver detected infinite numerical values

3.13.3.10 The analysis ran into a numerical problem

3.13.3.11 Damping parameters give unphisical values

3.13.3.12 The controller DLL was not running

3.13.3.13 Induced velocity was larger than relative velocity

3.13.3.14 The Steady BEM did not converge

3.13.3.15 File import

3.13.3.15.1 Unrecognized keywords

3.13.3.15.2 All offsets have to be zero at the root

3.13.3.15.3 The blade name was not found in the database

3.13.3.15.4 Part name not found

3.13.3.15.5 Parameter not used in the context

3.13.3.15.6 Values in table must be strictly increasing

3.13.3.15.7 Not a valid tag parameter

3.13.3.15.8 A tag cannot have a tag that influences placed after it

3.13.3.15.9 The name of the imported support section must be equal to the name of the existing support section

3.13.3.15.10 File for parameter X could not be loaded

3.13.3.15.11 Number of RNAs in the imported file error

3.13.3.15.12 Duplicated sensor

3.13.3.16 Python API errors

3.13.3.16.1 Python script maximum timeout exceeded

3.13.3.16.2 Could not find a Python executable

3.13.3.16.3 The Python script process exited with an error message

3.14 Data files

3.15 References

Docs > Theory Manual > Nomenclature > Terminology

Terminology

This section gives the definition of the terms used in Ashes.

2.1.2.1 Aerodynamical reference point
2.1.2.2 Angle of attack
2.1.2.3 Aspect ratio
2.1.2.4 Blade aerodynamical station
2.1.2.5 Blade length
2.1.2.6 Blade reference line
2.1.2.7 Blade shape
2.1.2.8 Chord length
2.1.2.9 Chordline midpoint
2.1.2.10 Fields
2.1.2.11 In-plane
2.1.2.12 Influence length
2.1.2.13 Load case
2.1.2.14 Load case set
2.1.2.15 Out-of-plane
2.1.2.16 Parameter tag
2.1.2.17 Pitch
2.1.2.18 Pitch axis
2.1.2.19 Scalar
2.1.2.20 Sensor
2.1.2.21 Time simulation job
2.1.2.22 Twist
2.1.2.22.1 Blade shape twist
2.1.2.22.2 Blade structure twist
2.1.2.22.3 Frame element twist
2.1.2.23 Wind angle