Comparative study between turbulence models in curved channels

Abstract

This paper presents a comparative study between results obtained in two-dimensional computational simulations performed with three different turbulence models: constant viscosity; Elder Model and k˗Ꜫ Model. The simulations were performed using the software Telemac 2D. These results were compared to data obtained from a study in experimental channel with trapezoidal cross-section and composed of straight stretches and curves. The main objective of this comparison is to explore how turbulence models affect the general behavior of the simulated flow. To support these comparisons, statistical analysis were adopted to quantify the differences between the velocity fields obtained in the simulations and that observed in the experimental channel. The results showed that, despite the theoretical limitations, the use of the simpler turbulence closure model, that is the constant turbulent viscosity, can lead to results as good as or better than those obtained with more sophisticated models.

Lagrangian Observations and Modeling of Turbulence Along a Tidally Influenced River

“…Turbulence in meandering rivers has also been studied via modeling approaches, including models based on the RANS equations (e.g., Almeida & Ota, 2020; Fischer‐Antze et al., 2009; Gholami et al., 2014; Kim et al., 2020; Rameshwaran & Naden, 2004; Wormleaton & Ewunetu, 2006), which rely on the performance of the turbulence models. More recently, the impact of turbulence closure schemes on the flow in curved channels has been investigated (e.g., Almeida & Ota, 2020; Kim et al., 2020). However, few studies have used high‐resolution Lagrangian field observations to validate a numerical model and to explore the flow‐following distributions of turbulence along a river.…”

“…Surface slope and secondary flows are often well predicted using a k‐ ϵ turbulence closure scheme (e.g., Demuren & Rodi, 1986; Parsapour‐Moghaddam & Rennie, 2017; Wormleaton & Ewunetu, 2006) even for strongly curved bends (Gholami et al., 2014). These studies have also shown that different turbulence models predicted slightly different simulated flow; for instance, Almeida and Ota (2020) demonstrated that the k‐ ϵ closure scheme could reliably reproduce the velocity all along the domain in their 2D‐simulation of a curved channel whereas the other model they tested, the Elder Model (an algebraic model), could not reproduce the velocity field both in sections of high curvature and in straight portions of the channel. Similarly, other studies have found that 3D velocity structure (and hence predictions of solute transport) are sensitive to the selected turbulence closure scheme, mainly due to the difficulty in perfectly reproducing the flow separation (Kim et al., 2020).…”

“…Here, we use high‐resolution Lagrangian field observations to validate a numerical model and to explore the flow‐following distributions of turbulence along a river. Turbulence in meandering rivers has also been studied via modeling approaches, including models based on the RANS equations (e.g., Almeida & Ota, 2020; Fischer‐Antze et al., 2009; Gholami et al., 2014; Kim et al., 2020; Rameshwaran & Naden, 2004; Wormleaton & Ewunetu, 2006), which rely on the performance of the turbulence models. More recently, the impact of turbulence closure schemes on the flow in curved channels has been investigated (e.g., Almeida & Ota, 2020; Kim et al., 2020).…”