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Example For Logarithmic Wind Profile Fit

WindDataSuite implements a module for fitting measured wind speed data to logarithmic wind speed profiles in analogy to the atmospheric boundary layer theory.
The fitting can be calculated for the 2-parameter model (friction velocity u*, roughness length z0) and for the 3-parameter model (friction velocity u*, roughness length z0, displacement height D).
Besides the classical method using linear regression, the logarithmic wind speed profile can also be calculated by using an 1-dimensional flow model. The linear regression is a pure mathematical fitting, whereas the 1-dimensional flow model will use all available relevant measured data in order to determine the actual physical processes within the air column.
In the following example, the height profiles of the measured wind speeds (black curves) have been fitted to the logarithmic wind speed profile (3-parameter model, red curves). The results from the linear regression are depicted in Fig.1, the results from the 1-dimensional flow model in Fig.2, respectively at two consecutive time steps.

Fig.1a Log. Fit Fig.1b Log. Fit
Fig.1: Logarithmic wind profile fit, 3-parameter model, linear regression
Fig.2a Log. Fit Fig.2b Log. Fit
Fig.2: Logarithmic wind profile fit, 3-parameter model, 1D flow model
 
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Data range : 1 year (365 days), sampling rate 10 minutes
Processed channels : 31 height levels of wind speed
31 height levels of vertical wind velocity
31 height levels of wind direction
Computing time : approx. 10 seconds
Processing time : approx. 1 minute