After extensive observations on the behavior of trackers based on their geometry, defense strategies, and damper arrangements, Soletrax has chosen a design that offers high wind stability by minimizing the exposed surface area. The adopted solution has been validated by the positive results obtained from aeroelastic wind tunnel testing on a single-row tracker matrix, conducted by the consulting firm RWDI.
By positioning one damper per semi-sail and adopting a defensive stance against high wind speeds—achieved by setting the first two rows at an intermediate angle to shield the inner rows, which in turn are set at a lower angle and always facing the wind—critical instability speeds of up to 210 km/h, the maximum test speed, have been reached.
From the outset, the inclusion of dampers in the design was chosen due to their significant contribution to reducing wind-induced instabilities. Numerous advanced dynamic studies were conducted to observe the effects of different types of dampers and to identify the optimal position along the tracker where their contribution is maximized. The benefit of including dampers is twofold: it increases the critical instability speed against wind and reduces the peak torsional stress on the tube.
For selecting the damper position, both the rotation between the penultimate and last post and the dynamic finite element analysis, which illuminates the post that most significantly reduces the maximum torsional stress in the tube, were considered. This results in a reduction of dynamic amplification effects.
Additionally, various analyses using RWDI’s 3D stability and buffeting response software augmented with their experience with full aeroelastic model research for the positioning of inner module rows yielded good results in terms of torsional stability against the wind.
Combining both aspects, the next step was to validate the theoretical analysis results with a wind tunnel test using a complete aeroelastic model, i.e., modeling several tracker rows as flexible structures, including dampers in their specific positions and characteristics. This test is the most comprehensive and precise for evaluating instability phenomena. Given the detailed and complex nature of this test, the RWDI technical team defined a procedure to select and discard alternatives so that the final chosen option would yield the best results, always exceeding the necessary stability requirements.
The initially selected option was the one ultimately tested. The obtained critical instability speeds for the final stow position strategy adopted (based on two first rows at 30º + eight rows at 5º) were more than satisfactory, exceeding the maximum tested speed limits (210 km/h).
The excellent results achieved are not coincidental. They are the result of years of experience, studies, and complex analyses conducted by the Soletrax team. Of course, we have also benefited from the work of the RWDI technical team, whose expert and intelligent advice has been crucial in decision-making.
This is a significant step in design, enabling us to continue working and advancing in photovoltaic structure projects, ensuring their reliability and safety.