Linking lacunarity to inertial particle clustering: Applications in solar photovoltaics

The presence of wind-flung debris is inevitable in solar photovoltaic (PV) systems, negatively altering production and lifespan by way of adhesion ( i.e. soiling) and forceful particle impacts. The propensity and magnitude of particle-to-panel interactions is largely dependent on environmental and panel-invoked turbulence, ultimately dictating local debris concentration and trajectories. This study confronts the mechanisms leading to PV panel soiling by developing a lacunarity-based framework for particle heterogeneity quantifying preferential concentration within asymmetric panel wakes due to inertial coupling . Drawing from established studies in multi-phase homogeneous isotropic turbulence (HIT), presented analysis demonstrates lacunarity as a comparable measure to Voronoï distributions for understanding particle clustering. Considering benchmark data obtained in experimental particle-laden HIT flow, global particle heterogeneity is shown to correlate with R e λ and ϕ v dependencies observed through Voronoï tessellations. Further expanding to consider PV panel wakes, Voronoï analysis and lacunarity uncover location-dependent variations in local particle clustering relating to asymmetric turbulent wake features. In total, this work represents a novel perspective of characterizing particle-laden turbulent flow by way of lacunarity-based heterogeneity and motivates preferential concentration as a complex feature impacting particle trajectories in PV systems . • Lacunarity-based heterogeneity is a marker for clustering in particle-laden flows. • Asymmetric solar panel wake turbulence modifies downstream debris clustering. • Clustering analysis in solar panel wakes informs soiling and structural impacts.