Turbulent Schmidt numbers for CFD analysis with various types of flowfield

Transverse jet in supersonic crossflows

Computational Fluid Dynamics (CFD) is increasingly being applied to model turbulent jet flows in practical applications ranging from gas turbine combustion to noise control and thrust augmentation....

Estimation of the Turbulent Schmidt Number from Experimental Profiles of Axial Velocity and Concentration for High-Reynolds-Number Jet Flows

CFD simulations and experimental validation of homogenisation curves and mixing time in stirred Newtonian and pseudoplastic liquids

This work presents a numerical study on the turbulent Schmidt numbers in jets in crossflow. This study contains two main parts. In the first part the problem of the proper choice of the turbulent Schmidt number in the Reynolds-Averaged Navier-Stokes (RANS) jet in crossflow mixing simulations is outlined. The results of RANS employing the shear-stress transport (SST) model of Menter and its curvature correction modification and different turbulent Schmidt number values are validated against experimental data. The dependence of the “optimal” value of the turbulent Schmidt number on the dynamic RANS model is studied. Furthermore a comparison is made with the large-eddy simulation (LES) results obtained using the WALE (Wall-Adapted Local Eddy Viscosity) model. The accuracy given by LES is superior in comparison to RANS results. This leads to the second part of the current study, in which the time-averaged mean and fluctuating velocity and scalar fields from LES are used for the evaluation of the turbulent viscosities, turbulent scalar diffusivities, and the turbulent Schmidt numbers in a jet in crossflow configuration. The values obtained from the LES data are compared with those given by the RANS modeling. The deviations are discussed and the possible ways for the RANS model improvements are outlined.© 2012 ASME

A Numerical Study on the Turbulent Schmidt Numbers in a Jet in Crossflow

The effect of Schmidt number on turbulent scalar mixing in a jet-in-crossflow

The adequacy and accuracy of the constant Schmidt number assumption in predicting turbulent scalar fields in jet-in-crossflows are assessed in the present work. A round jet injected into a confined crossflow in a rectangular tunnel has been simulated using the Reynolds-Averaged Navier-Stokes equations coupled with the standard k-e turbulence model. A semi-analytical qualitative analysis was made to guide the selection of Schmidt number values. A series of parametric studies were performed, and Schmidt numbers ranging from 0.2 to 1.5 and jet-to-crossflow momentum flux ratios from 8 to 72 were tested. The principal observation is that the Schmidt number does not have an appreciable effect on the species penetration, but it does have a significant effect on species spreading rate in jet-in-crossflows, especially for the cases where the jet-to-crossflow momentum flux ratios are relatively small. A Schmidt number of 0.2 is recommended for best agreement with data. The limitations of the standard k–e turbulence model and the constant Schmidt number assumption are discussed.Copyright © 1999 by ASME

/pdf/the-effect-of-schmidt-number-on-turbulent-scalar-mixing-in-a-uduxwcoco7.pdf

Guangbin He

Papers

The effect of Schmidt number on turbulent scalar mixing in a jet-in-crossflow

The Effect of Schmidt Number on Turbulent Scalar Mixing in a Jet-in-Crossflow