Spatially-averaged flow statistics within a canopy of large bluff bodies: Results from direct numerical simulations

• Published in: Acta geophysica Vol. 56; no. 3; pp. 862 - 875
• Main Authors: Coceal, Omduth, Thomas, T. Glyn, Belcher, Stephen E.
• Format: Journal Article
• Language: English
• Published: Heidelberg SP Versita 01.09.2008; Versita; Springer Nature B.V
• Subjects: bluff bodies; direct numerical simulations; double-averaging methodology; Earth and Environmental Science; Earth Sciences; Fluid dynamics; Geophysics; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Research Article; rough-wall channel flow; Simulation; Structural Geology; Turbulence; turbulent channel flow; direct numerical simulations; double-averaging methodology; bluff bodies; turbulent channel flow; rough-wall channel flow
• ISSN: 1895-6572; 1895-7455
• DOI: 10.2478/s11600-008-0025-y

The flow within a canopy of large bluff bodies is highly turbulent and spatially heterogeneous. Results from direct numerical simulations over groups of cubical obstacles are analysed using the double-averaging methodology. The obstacles occupy a significant fraction of the canopy space; this gives rise to substantial dispersive stresses within the canopy. The underlying bluff-body turbulent dynamics is different from typical canopy turbulence, and this is reflected in the double-averaged statistics. The spatially-averaged velocities, stresses and drag force depend significantly upon the layout of the obstacles. An ongoing challenge is to parameterise these spatially-averaged quantities in terms of the obstacle geometry and layout.