On the Values for the Turbulent Schmidt Number in Environmental FlowsReport as inadecuate


On the Values for the Turbulent Schmidt Number in Environmental Flows


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1

Department of Civil, Construction and Environmental Engineering DICEA, University of Napoli -Federico II-, Napoli 80125, Italy

2

Department of Earth Science and Engineering, Faculty of Engineering, Imperial College, SW7 2AZ London, UK

3

Department of Civil and Environmental Engineering, University of California, Davis, CA 95616, USA

4

Department of Civil Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada

5

Hydro-environmental Research Centre, School of Engineering, Cardiff University, The Parade, CF24 3AA Cardiff, UK





*

Author to whom correspondence should be addressed.



Academic Editor: Meir Teitel

Abstract Computational Fluid Dynamics CFD has consolidated as a tool to provide understanding and quantitative information regarding many complex environmental flows. The accuracy and reliability of CFD modelling results oftentimes come under scrutiny because of issues in the implementation of and input data for those simulations. Regarding the input data, if an approach based on the Reynolds-Averaged Navier-Stokes RANS equations is applied, the turbulent scalar fluxes are generally estimated by assuming the standard gradient diffusion hypothesis SGDH, which requires the definition of the turbulent Schmidt number, Sct the ratio of momentum diffusivity to mass diffusivity in the turbulent flow. However, no universally-accepted values of this parameter have been established or, more importantly, methodologies for its computation have been provided. This paper firstly presents a review of previous studies about Sct in environmental flows, involving both water and air systems. Secondly, three case studies are presented where the key role of a correct parameterization of the turbulent Schmidt number is pointed out. These include: 1 transverse mixing in a shallow water flow; 2 tracer transport in a contact tank; and 3 sediment transport in suspension. An overall picture on the use of the Schmidt number in CFD emerges from the paper. View Full-Text

Keywords: environmental fluid mechanics; computational fluid dynamics; Reynolds-averaged Navier-Stokes equations RANS; turbulent Schmidt number environmental fluid mechanics; computational fluid dynamics; Reynolds-averaged Navier-Stokes equations RANS; turbulent Schmidt number





Author: Carlo Gualtieri 1,* , Athanasios Angeloudis 2, Fabian Bombardelli 3, Sanjeev Jha 4 and Thorsten Stoesser 5

Source: http://mdpi.com/



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