Turbulent Flow Around a Semi-Submerged Rectangular Cylinder

Abstract

The present work is motivated by phenomena occurring in the flow field around structures partly submerged in water. A three- dimensional (3D) unsteady flow around a rectangular cylinder is studied for four different submergence ratios by using computational fluid dynamics (CFD) tools with the large eddy simulation (LES) turbulence model. The simulation results are compared to particle image velocimetry (PIV) measurements at the Reynolds number Re¼12,100 and the Froude number Fr¼0.26. The focus in our investigation is on the characterization of the behavior of vortex structures generated by separated flow. Another target in the study is to obtain a better knowledge of the\ud hydrodynamic forces acting on a semi-submerged structure. The computed force coefficients are compared with experimental measurements

Drag and lift contribution to the incipient motion of partly submerged flooded vehicles

“…Drag coefficient values are in the lower range experimentally found by Malavasi and Guadagnini (2007) for a fully submerged rectangular cylinder in sub-critical conditions. Drag and lift coefficients for low Froude number show a strong similarity with the values evaluated from the numerical simulations of a semi-submerged rectangular cylinder by Arslan et al (2013). Drag and lift coefficients increase when Froude number decreases (e.g.…”

“…There are only a few references for partially-submerged conditions and subcritical flow conditions (Malavasi and Guadagnini, 2003;Arslan et al, 2013) and no references for partially submerged complex objects leaning on a channel bed under both subcritical and supercritical flows. Transition to supercritical conditions may substantially alter the pressure distributions and the resulting drag and lift forces, as already observed in the study of hydrodynamics of marine vehicles (Chapman, 1972;Savitsky and Ward Brown, 1976;Faltinsen, 2006).…”

Hydrodynamics of pedestrians' instability in floodwaters

“…As shown by Arslan et al (2013), Zhang et al (2014) and by Arrighi et al (2015), lift force can also play a significant role for partly submerged objects. The average density of the human body (ρ P = 1062 kg m −3 ) is generally assumed equal to the density of muddy water; thus, ρ P is substituted with ρ in Eq.…”

Numerical and Experimental Study of the Solo Duck Wave Energy Converter

“…Because a rectangular angle is the infinite approximation of a sufficiently large curvature, the leading and trailing corners act as the fixed flow separation points for the geometry. These vortex generation phenomena are extensively studied in [36][37][38][39]. The direction of P and Q is perpendicular to plane of the main flow with the polarity be determined so that the peripheral velocity of the vortex follows the main flow.…”