Recent developments in multiscale forcing for enhanced mixing
| Autor: | Bernardus J. Geurts, Thiago Cardoso de Souza |
|---|---|
| Přispěvatelé: | MESA+ Institute, Multiscale Modeling and Simulation, Center for Computational Energy Research, Multi-scale Modelling of Multi-phase Flows, Energy Technology |
| Rok vydání: | 2018 |
| Předmět: |
Pipe flow
Materials science General Computer Science Turbulence General Engineering Direct numerical simulation Orifice plate Laminar flow Mechanics Immersed boundary method 01 natural sciences n/a OA procedure 010305 fluids & plasmas Physics::Fluid Dynamics Classical mechanics Enhanced mixing Incompressible flow 0103 physical sciences Multiscale forcing 010306 general physics Bunsen flame Body orifice Turbulence modulation |
| Zdroj: | Computers and fluids, 176, 353-365. Elsevier Computers & Fluids, 176, 353-365. Elsevier |
| ISSN: | 0045-7930 |
| DOI: | 10.1016/j.compfluid.2017.06.014 |
| Popis: | We discuss methods of multiscale forcing to enhance the mixing efficiency of an incompressible flow. To introduce a variety of length- and time-scales into a flow, we focus on two methods. First, we concentrate on effects due to guiding a fluid over a complex-shaped object placed in the flow domain. Specifically, we apply direct numerical simulation to predict flow through a cylindrical pipe in which a periodic array of orifice plates with a fractal perimeter is mounted. To represent the complex orifice, a volume penalisation immersed boundary method is used. Adding a periodic array of fractal orifice plates, derived from the Koch snowflake, to a cylindrical pipe is shown to increase the average laminar stretching rate by a factor of up to five, compared to pipe flow without orifice plates. Second, we consider the inclusion of multiple length- and time scales at inflow boundaries to enhance mixing efficiency for combustion in Bunsen-type flames. By using a combination of large- and small-scale flow perturbations at an inflow, a two-fold increase of flame wrinkling and flame intensity could be realised. The scale-dependency of the intensification of the combustion is investigated, showing a narrow range of length-scales with strongest response, reminiscent of ‘resonant turbulence’ conditions. |
| Databáze: | OpenAIRE |
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