A Review of Embedded Large Eddy Simulation for Internal Flows

Abstract

When scale-resolving simulation approaches are employed for the simulation of turbulent flow, computational cost can often be prohibitive. This is particularly true for internal wall-bounded flows, including flows of industrial relevances which may involve both high Reynolds number and geometrical complexity. Modelling the turbulence induced stresses (at all scales) has proven to lack requisite accuracy in many situations. In this work we review a promising family of approaches which aim to find a compromise between cost and accuracy; hybrid RANS-LES methods. We place particular emphasis on the emergence of embedded large eddy simulation. These approaches are summarised and key features relevant to internal flows are highlighted. A thorough review of the application of these methods to internal flows is given, where hybrid approaches have been shown to offer significant benefits to industrial CFD (relative to an empirical broadband modelling of turbulence). This paper concludes by providing a cost-analysis and a discussion about the emerging novel use-modalities for hybrid RANS-LES methods in industrial CFD, such as automated embedded simulation and multi-dimensional coupling.

Comparison of low Reynolds number turbulence and conjugate heat transfer modelling for pin-fin roughness elements

“…A hybrid URANS-Numerical-LES (RANS/NLES) model can predict the flow behaviour of a seal flow within 5% accuracy [22] . This is also the case for internal wall-bounded flows [23] , demonstrating that RANS/LES has good capabilities to model turbulent flow fields while being less computationally expensive than full LES.…”

Turbulence modeling and simulation advances in CFD during the past 50 years

“…Indeed, the choice among the different methodologies available strongly depends on the physical problem considered and the type of answers which are expected. In particular the hybrid range of techniques, considering its flexibility, can encompass many practical situations [10,11,213,214] and are a good alternative, with the accuracy of LES and the speed of RANS. Some problems like intermittency would need more investigation.…”

Experimental and Numerical Assessment of Iso-Flux Cooling with Low Reynolds Pulsating Water Flow

“…To model these kinds of scenarios, the large-eddy simulation (LES) method can be used, which often produces satisfactory results for iso-flux models, as demonstrated by the work of Ould-Rouiss et al [ 14 ] and Holgate et al [ 15 ].…”