EnvironmentSTUDIO flow (es-flow for short) is a library for analysing and modeling atmospheric and marine boundary layers.

While es-flow can be used for any turbulent boundary layer analysis, its main focus is for wind and tidal site characterisation - generating the ‘best fit’ of analytical models to measured velocity data.

A key strength of es-flow is the adem. This extremely robust method allows users to:

  • determine detailed turbulence information from instruments like LiDAR
  • characterise turbulence and shear beyond tip height of even the biggest offshore wind turbines
  • characterise coherent structure in turbulence, crucially important for fatigue loading in wind turbines.
Atmospheric Boundary Layer PSD determined with es-flow

Atmospheric Boundary Layer PSD determined with es-flow.


The es-flow library provides: [1]

  1. Parameterised profiles
    • Mean Velocity (using power law, logarithmic law, MOST or Lewkowicz relations)
    • Mean Veer (Using Monin-Obukhov approach)
    • Reynolds Stress u'w' (using Lewkowicz relations)
    • Reynolds Stress u'u', u'v', u'w', v'v', v'w', w'w' (using the adem)
    • Spectra Sij (using Kaimal, von Karman)
    • Spectra Sij (using adem)
    • Integral turbulent intensity and lengthscale I, l
  2. Best fit parameter sets
    • To describe the above profiles analytically (given measured velocity data from an instrument).
In future, generation of artificial flow fields for simulation purposes might be considered. This would overlap with - or replace - utilities like TurbSim to produce, for example:
  • .wnd fields input to BEM or FVM models like Bladed, FAST and TurbineGRID
  • Inlet boundary conditions for DES or LES codes
Atmospheric Boundary Layer velocity profile, fitted with es-flow

Atmospheric Boundary Layer velocity profile, fitted with es-flow.


At Octue, es-flow is used to:

  • Provide a basis for developing and validating new processes, like the adem, for characterising Atmospheric Boundary Layers.
  • Process LiDAR and ADCP datasets from raw instrument files.
  • Apply windowed analyses to time series data, for flow characterisation.
  • Generate load cases for FAST, Bladed and our own TurbineGRID aerodynamic wind turbine analysis tools.

We’d like to hear about your use case. Please get in touch!

We use the GitHub Issue Tracker to manage bug reports and feature requests.


[1]Not all of this functionality is implemented yet!