On the theory of SODAR measurement techniques (final reporting on WP1, EU WISE project NNE5-2001-297)

Antoniou, I; Jorgensen, HE; Ormel, F; Bradley, SG; von Hünerbein, S; Emeis, S; Warmbier, G

Abstract

The need for alternative means to measure the wind speed for wind energy purposes has increased with
the increase of the size of wind turbines. The cost and the technical difficulties for performing wind
speed measurements has also increased with the size of the wind turbines, since it is demanded that the
wind speed has to be measured at the rotor center of the turbine and the size of both the rotor and the
hub height have grown following the increase in the size of the wind turbines. The SODAR (SOund
Detection And Ranging) is an alternative to the use of cup anemometers and offers the possibility of
measuring both the wind speed distribution with height and the wind direction.
At the same time the SODAR presents a number of serious drawbacks such as the low number of
measurements per time period, the dependence of the ability to measure on the atmospheric conditions
and the difficulty of measuring at higher wind speeds due to either background noise or the neutral
condition of the atmosphere.
Within the WISE project (EU project number NNE5-2001-297), a number of work packages have been
defined in order to deal with the SODAR. The present report is the result of the work package 1. Within
this package the objective has been to present and achieve the following:
- An accurate theoretic model that describes all the relevant aspects of the interaction of the sound
beam with the atmosphere in the level of detail needed for wind energy applications.
- Understanding of dependence of SODAR performance on hard- and software configuration.
- Quantification of principal difference between SODAR wind measurement and wind speed
measurements with cup anemometers with regard to power performance measurements.
The work associated to the above is described in the work program as follows:
a) Draw up an accurate model of the theoretic background of the SODAR. The necessary depth is
reached when the influences of various variables in the model on the accuracy of the measurement
have been assessed.
b) Describe the general algorithm SODAR uses for sending the beam and measuring the reflections.
Describe the influence of various settings on the working of the algorithm.
c) Using the data set from work package two analyse the differences between point measurements and
profile measurements.
All the above issues are addressed in the following report

Citation

Antoniou, I., Jorgensen, H., Ormel, F., Bradley, S., von Hünerbein, S., Emeis, S., & Warmbier, G. (2003). On the theory of SODAR measurement techniques (final reporting on WP1, EU WISE project NNE5-2001-297)

• Report Type: Project Report
• Publication Date: Jan 1, 2003
• Deposit Date: Aug 19, 2010
• Publicly Available Date: Apr 5, 2016