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DY: Fachverband Dynamik und Statistische Physik

DY 57: Poster: Statistical Physics; Critical Phenomena; Stochastic Thermodynamics; Extreme Events; Data Analytics

DY 57.14: Poster

Donnerstag, 19. März 2020, 15:00–18:00, P1C

CFD simulation of the wind field over a terrain with sand fences: Critical spacing for the wind shear velocity — Izael Araújo Lima¹, •Eric Josef Ribeiro Parteli², Yaping Shao², José Soares Andrade Jr.¹, Hans Jürgen Herrmann^1,3, and Ascânio Dias Araújo¹ — ¹Departamento de Física, Universidade Federal do Ceará, Fortaleza, Brazil — ²Department Geowissenschaften, Universität zu Köln, Cologne, Germany — ³PMMH, ESPCI Paris, France

Sand fences are often erected to reduce wind speed and prevent aeolian soil erosion. However, the search for the most efficient array of fences by means of field experiments alone poses a challenging task. Here we apply Computational Fluid Dynamic simulations to investigate the three-dimensional structure of the turbulent wind field over an array of fences. We find that the area of soil associated with wind shear velocity values smaller than the minimal threshold for sand transport has two regimes, depending on the spacing L_x between the fences. When L_x is smaller than a critical value L_xc, the wake zones associated with each fence are inter-connected (regime A), while these wake zones appear separated from each other (regime B) when L_x exceeds this critical value of spacing. The system undergoes a second order phase transition at L_x = L_xc, with the cross-wind width of the protected zone scaling with [1−L_x/L_xc]^β in regime A, with β ≈ 0.32. Our findings have implication for a better understanding of aeolian transport in the presence of sand fences, as well as to develop optimization strategies for anti-desertification measures.