Wind Flow Characterisation over a PV Module through URANS Simulations and Wind Tunnel Optical Flow Methods

Francesco Castellani,Matteo Becchetti,Davide Astolfi,Gianluca Rossi,Francesco Natili,Abdelgalil Eltayesh,Lorenzo Capponi,Tommaso Tocci

doi:10.3390/en14206546

Francesco Castellani, Matteo Becchetti + Show 6 more

Open Access

https://doi.org/10.3390/en14206546

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Journal: Energies	Publication Date: Oct 12, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: University of Perugia, Benha University

Abstract

Despite their simplicity, photovoltaic (PV) modules are often arranged in structures that can be affected by severe and complex wind loads: in this context, the wind flow and the dynamic excitation induced by vortex shedding can introduce unexpected aeroelastic responses. This work introduces a novel wind tunnel application of experimental techniques to address this issue by the use of flow visualisation and video postprocessing, through the optical flow algorithm. Numerical simulations based on unsteady Reynolds-averaged Navier–Stokes (RANS) models are performed and compared against the experimental wind tunnel tests on a PV panel that was also instrumented with pressure taps. A setup with a 65∘ tilt angle was examined because, based on preliminary analyses, it was considered interesting for the free flow–wake transition associated with the dynamic response of the PV panel. The comparison of the experimental and numerical average wind fields supported that the proposed optical flow method was appropriate for characterising the wake of the panel, because there was enough seeding to perform the video postprocessing. Experiments and numerical predictions were compared as regards the average pressure distribution on the panel surfaces, and the average percentage was in the error of 7%; this supports that the URANS method was capable of reproducing the average behaviour of the panel, as well as for the selected configuration, which is particularly challenging. Furthermore, the simulated and measured power spectral densities of the wind speed were compared, and this resulted in the numerical model quite faithfully reproducing the frequency of the peak at 5 m/s, while the error was in the order of 20% for the 10 m/s case; this supports that, despite the URANS approach being affected by well-known critical points regarding the simulation of instantaneous quantities, it can be employed to elaborate information that can be particularly useful for the structural design of the panel. This kind of result can be considered as a first step, obtained with simplified and affordable methods, towards a characterisation of the dynamic behaviour of a PV panel in a real-world setup.

Highlights

IntroductionThe fast development of the exploitation of solar and wind energy on large scales through the use of photovoltaic (PV) panels [1] has led to the diffusion of multimegawatt plants with very large structures often installed in open fields [2]
The detailed information on the effect of the wind loading on the PV panels, as well as the flow as the field characteristics can be illustrated through an analysis of the static pressure distribution on the PV surfaces
The general motivation for this analysis was that a PV panel operating in field can be subjected to a complex scenario of wind loads, and its structural design should be conceived of consequent to this

Summary

Introduction

The fast development of the exploitation of solar and wind energy on large scales through the use of photovoltaic (PV) panels [1] has led to the diffusion of multimegawatt plants with very large structures often installed in open fields [2]. This fact has posed the problem of the correct estimation of wind loads [3,4,5] to optimally develop the structural design. Experimental measurements on scaled models or portions of a large structure can be very important for the validation of numerical models, which can more manage complex configurations

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