Numerical modelling of trapezoidal weir flow with RANS, LES and DES models

Oksal, N Goksu Soydan; Aköz, M. Sami; Şimşek, Oğuz

doi:10.1007/s12046-020-01332-2

Cited by 14 publications

(2 citation statements)

References 19 publications

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“…Hargreaves et al [19] studied the two-dimensional (2D) structure of free flow over a rectangular broad-crested weir using the Fluent software package. Soydan-Oksal et al [20] performed a similar study to examine the salient features of the flow over a trapezoidal broad-crested weir. They employed computational models based on the Reynolds-averaged Navier-Stokes equations in two-and three-dimensional settings.…”

Section: Introductionmentioning

confidence: 99%

Free Flow and Discharge Characteristics of Trapezoidal-Shaped Weirs

Zerihun¹

2020

Fluids

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A number of studies have considered the effects of weir design variations on the free- and submerged-flow characteristics of trapezoidal broad-crested weirs. It appears that the hydraulics of short-crested weir flows have received little attention; thus, the current knowledge is incomplete. By systematically analyzing a large set of experimental data, the present study aims to fill in this knowledge gap and to provide a complete description of the discharge characteristics of trapezoidal-shaped weirs, including the salient features of two-dimensional weir flows. The analysis of the axial free-surface profiles for short-crested weir flows attested that the location of the nearest station for the correct measurement of the overflow depth under free-flow conditions is at η0 from the heel of the weir, where η0 is the upstream free-surface elevation. Additionally, an empirical equation for the free-flow discharge coefficient is proposed as being valid for a trapezoidal-shaped weir with varying upstream- and downstream-face slopes. The results of this investigation reveal that the streamline curvature and the slopes of the upstream and downstream weir faces significantly affect the streamwise flow patterns and, hence, the free-flow discharge.

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Section: Introductionmentioning

confidence: 99%

Free Flow and Discharge Characteristics of Trapezoidal-Shaped Weirs

Zerihun¹

2020

Fluids

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“…To address this issue, researchers have proposed the use of High-Resolution Interface Capturing (HRIC) schemes, which combine upwind and downwind interpolations to effectively capture and maintain the sharp interfaces between different phases [28,29]. The VOF model captures the free surface by (i) determining the free surface location in cells, (ii) considering a sharp intersection between air and water, and (iii) applying boundary conditions on the intersection [30] The interface between air and water is tracked by solving the continuity equation for ζ, as follows.…”

Section: Mathematical Formulationsmentioning

confidence: 99%

Computational analysis of air bubble-induced frictional drag reduction on ship hulls

Mohammadpour,

Salehi,

Garaniya

et al. 2024

J Mar Sci Technol

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About 60% of marine vessels’ power is consumed to overcome friction resistance between the hull and water. Air lubrication can effectively reduce this resistance and lower fuel consumption, and consequently emissions. This study aims to analyze the use of a gas-injected liquid lubrication system (GILLS) to reduce friction resistance in a real-world scenario. A 3D computational fluid dynamics model is adopted to analyse how a full-scale ship (the Sea Transport Solutions Designed Catamaran ROPAX ferry) with a length of 44.9 m and a width of 16.5 m is affected by its speed and draught. The computational model is based on a volume of fluid model using the k-ꞷ shear stress transport turbulence model. Results show that at a 1.5 m draught and 20 knots cruising speed, injecting 0.05 kg/s of compressed air into each GILLS unit reduces friction resistance by 10.45%. A hybrid model of natural air suction and force-compressed air shows a friction resistance reduction of 10.41%, which is a promising solution with less required external power. The proposed technique offers improved fuel efficiency and can help to meet environmental regulations without engine modifications.

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