Fluid Mechanics and Acoustics Laboratory - UMR 5509

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Home > Teams > Turbulence & Instabilities > Publications T&I et posters doctorants > Former five-year period > Publications T&I 2017

Article in Comput. Fluids (2017)

Mixing in modulated turbulence. Analytical results

Wouter J.T. Bos, Robert Rubinstein

Mixing in modulated turbulence. Analytical results

Recent numerical results show that if a scalar is mixed by periodically forced turbulence, the average mixing rate is directly affected for forcing frequencies small compared to the integral turbulence frequency. We elucidate this by an analytical study using simple turbulence models for spectral transfer. Adding a large amplitude modulation to the forcing of the velocity field enhances the energy transfer and simultaneously diminishes the scalar transfer. Adding a modulation to a random stirring protocol will thus negatively influence the mixing rate. We further derive the asymptotic behavior of the response of the passive scalar quantities in the same flow for low and high forcing frequencies.

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