Direct numerical simulation–based Reynolds-averaged closure for bubble-induced turbulence

Abstract

Budgets of the turbulent kinetic energy from direct numerical simulations (DNSs) of disperse bubbly channel flows are used to develop a model for bubble-induced turbulence in the Euler-Euler Reynolds-averaged framework. First, an appropriate time scale is selected. Second, links between the unclosed terms in the transport equations of the turbulence quantities and the DNS data for small bubbles are established. Third, a suitably chosen iterative procedure employing the full Reynolds-averaged model provides suitable coefficients for the closure of the terms resulting from bubble-induced turbulence while largely removing the influence of others. At the same time these results validate the closure, exhibiting very good agreement with the DNS and better performance than the standard closures. The model is now ready for use and can be employed in practical Euler-Euler simulations.Received 10 November 2016DOI:https://doi.org/10.1103/PhysRevFluids.2.034301©2017 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasDrops & bubblesMultiphase flowsTurbulenceFluid Dynamics