Eddy resolving simulations in aerospace – Invited paper (Numerical Fluid 2014)

Abstract

a b s t r a c tThe future use of eddy resolving simulations (ERS) such as Large Eddy Simulation (LES), Direct Numerical Simulation (DNS) and related approaches in aerospace is explored. The turbulence modeling requirements with respect to aeroengines and aircraft is contrasted. For the latter, higher Reynolds numbers are more prevalent and this especially gives rise to the need for the hybridization of ERS methods with Reynolds Averaged Navier-Stokes (RANS) approaches. Zones where future use of pure ERS methods is now possible and those where hybridizations with RANS will be needed is outlined. The major focus is the aeroengine for which the component scales are much smaller. This gives rise to generally more benign Reynolds numbers. The use of eddy resolving methods in a wide range of zones in an aeroengine is discussed and the potential benefits and also cost drawbacks with such approaches noted. The tension when using such computationally intensive calculations in an area where the coupling of components and even the airframe and engine is becoming increasingly important is explored. Also, the numerical methods and meshing requirements are considered and the implications of ERS methods for future numerical algorithms. It is postulated that such simulations are ready now for niche uses in industry. However, to perform the scale of simulations that industry requires, to meet pressing environmental needs, challenges remain. For example, there is the need to develop optimal numerical methods that both map to the accuracy requirements for ERS and also future computer architectures.

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

“…This modeling was initially developed to simulate atmospheric and geophysical flows and is now more and more used to get particular details and some insights on flow structures [5,6]. The Scale resolving simulation (SRS) methods including DNS and LES are beginning to be applied in aerospace industries [7,8]. In the past two decades, more recent hybrid RANS/LES models that combine in various ways the RANS and the LES methods have been proposed for simulating turbulent flows of practical interest allowing a second life to RANS closures.…”

“…Some problems like intermittency would need more investigation. Many of the problems discussed are encountered in aerospace industry in which CFD plays an increasingly crucial role [7] and in which various types of methods have their place for different uses [8,58,215,216]. The question is also open whether modern data-driven techniques may be able to find optimal models in a user-defined sense [217,218].…”

Experiments on Tuned UHBR Open-Test-Case Fan ECL5/CATANA: Performance and Aerodynamics

“…The goal of the study presented here is to provide a benchmark dataset on a geometry that is representative of near future architectures that allows detailed validation and calibration of prediction methods on multiple levels of fidelity for the whole research community. This ranges from reduced order models as described by [13,14] to scale resolving coupled methods which are on the verge of being accessible to this type of architecture [15,16,17,18,19].…”

Extended integral wall-model for large-eddy simulations of compressible wall-bounded turbulent flows

“…In the frame of this work, the aim is to develop a wallmodel capable of taking into account the physical phenomena encountered in turbomachinery systems. Usually, in turbomachinery flows, Mach numbers are up to 1.5, [39][40][41][42][43] Reynolds numbers 44,45 between 10 5 and 10 7 , and temperature gradients in the order of ten to hundred Kelvin. 46 As pointed out by Tyacke and Tucker,47 if the flow in low-pressure turbines can be simulated with LES due to their relatively low-Reynolds number, the flows in the other components require a wallmodeling in order to reduce computational requirements at high Reynolds numbers.…”