Mixing in modulated turbulence. Analytical results

Autor: Wouter J. T. Bos, Robert Rubinstein
Přispěvatelé: Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Newport News
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Computers and Fluids
Computers and Fluids, Elsevier, 2017, ⟨10.1016/j.compfluid.2016.10.024⟩
ISSN: 0045-7930
DOI: 10.1016/j.compfluid.2016.10.024⟩
Popis: 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 behaviour of the response of the passive scalar quantities in the same flow for low and high forcing frequencies.
Comment: in Computers & Fluids, 2016
Databáze: OpenAIRE