Large eddy simulation of compressible transitional cascade flows

Matsuura, Kota; Kato, Chisachi

doi:10.2495/afm06049

Cited by 6 publications

(10 citation statements)

References 6 publications

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“…With the enormous development in computer science, the large eddy simulation (LES) method has been used in compressor cascade flow simulation in recent years, utilizing a large amount of computer resources (Matsuura & Kato, 2007;McMullan & Page, 2011;Teramoto, 2005;Zaki, Wissink, Durbin, & Rodi, 2009). Modeling threedimensional corner separation requires the CFD code to be very robust.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of RANS turbulence models in simulating the corner separation of a high-speed compressor cascade

Zhang

2015

Engineering Applications of Computational Fluid Mechanics

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A typical high-speed compressor cascade flow is simulated using an eddy viscosity model and a Reynolds stress model. Based on comparisons with experimental results, the simulation accuracies of the two turbulence models are evaluated, and some recommendations are provided for further research. Inside the cascade flow passage, the simulation accuracies of both turbulence models decrease because of the corner effect. Downstream of the blade, the wake mixing influence, and thus the flow loss, is under-predicted by both turbulence models. Compared with the linear eddy viscosity model, the modification of the simulation accuracy with regard to endwall flow prediction using the Reynolds stress model is limited, which only occurs at a highly positive incidence angle. The corner separation strength and wake mixing influence predicted by the eddy viscosity model are surpassed by those of the Reynolds stress model. At a negative incidence angle, the simulation result of the Reynolds stress model is proved to be physically unreasonable according to the flow loss prediction.

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Section: Introductionmentioning

confidence: 99%

Evaluation of RANS turbulence models in simulating the corner separation of a high-speed compressor cascade

Zhang

2015

Engineering Applications of Computational Fluid Mechanics

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“…Based on the findings of this work, further efforts were made to improve turbulence modelling of the flow in turbomachinery [10]. The influence of freestream turbulence on transition on turbine blades has been investigated using LES [11], highlighting the need for reasonably posed inlet conditions. Simulations of a linear compressor cascade at a moderate Reynolds number was studied by Zaki et al [12] -the periodically passing wake caused the suction-side flow to separate and roll-up into discrete K-H vortices.…”

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of a Controlled Diffusion Compressor Cascade

McMullan

Page

2010

Flow Turbulence Combust

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In this research a Controlled Diffusion (CD) compressor cascade stator blade is simulated at a Reynolds number of ∼ 700, 000, based on inflow velocity and chord length, using Large Eddy Simulation (LES). A wide range of flow inlet angles are computed, including conditions near the design angle, and at high negative and positive incidence. At all inlet angles the surface pressure distributions are well-predicted by the LES. Near the design angle the computed suction side boundary layer thickness agrees well with experimental data, whilst the pressure side boundary layer is poorly predicted due to the inability of LES to capture natural boundary layer transition on the present grid. A good estimation of the loss is computed near the design angle, whilst at both high positive and negative incidences the loss is less well predicted owing to discrepancies between the computed and experimental boundary layer thickness. At incidences above the design angle a laminar separation bubble forms near the leading edge of the suction surface, which undergoes a transition to turbulence. Similar behaviour is noted on the pressure surface at negative incidence. At high negative incidence contra-rotating vortex pairs are found to form around the leading edge inThe authors would like to thank Rolls-Royce plc and the UK Technology Strategy Board for the funding this work under the CFMS Core Programme (TP/L3001H). The simulations in this study were performed on HECToR, the UK National Supercomputing Facility, under the UKAAC-2 Framework, EPSRC grant number EP/F005954/1. response to an unsteady stagnation line across the span of the blade. Such structures are not apparent in time-averaged statistical data due to their highly-transient nature.

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“…The effect of small-scale turbulence embedded within the wakes was studied by Wissink et al [4], who concluded that while the large-scale motion of the wake triggers the Kelvin-Helmholtz (K-H) instability on the suction side of the blade, the small-scale disturbances embedded into the wake flow seed the transition to turbulence in the shear layer flow. Matsuura and Kato [5] used LES to predict transitional flow in a turbine cascade and found that the dominant unsteady behaviour of the transitional boundary layers depends upon the presence of simulated freestream turbulence.…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of a compressor cascade and the influence of spanwise domain

McMullan

Page

2011

Proceedings of the Institution of Mechanical Engineers, Part A:

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A controlled diffusion compressor cascade is studied using large eddy simulation (LES). The aim of this study is to assess the capability of LES to be used in an industrial context. The Reynolds number is approximately 700 000 based on chord length and inlet velocity. A 'thinslice' representation of the cascade is used as the reference grid, and the influence of a narrow span is studied by comparison simulations with a domain that has a span five times larger than the thin-slice grid. While the instantaneous flow-fields of the thin-slice and wide-domain simulations are qualitatively similar, the thin-slice simulations suffer from flow confinement problems caused by the imposition of the narrow span. The non-unity axial velocity density ratio of the flow enforces the use of inviscid wall spanwise boundaries, which have a parasitic influence on the development of the flow in the thin-slice simulations. The resultant data obtained from the thinslice simulations are therefore compromised and the computed loss estimation is considered unreliable. However, when comparing mean quantities such as surface pressure and boundary layer growth the narrow does give reasonable predictions. While the inviscid spanwise walls also affect the flow near the boundaries in the wide domain simulations, there is sufficient region of span from which reliable flow data and loss estimations can be obtained. For blade flows at off-design conditions, a span of 20 per cent of the blade chord is sufficient to give good agreement with experimental data. This incurs a computational cost that may be too high to incorporate parametric LES studies into the design cycle of turbomachinery components with current computers.

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Large eddy simulation of compressible transitional cascade flows

Cited by 6 publications

References 6 publications

Evaluation of RANS turbulence models in simulating the corner separation of a high-speed compressor cascade

Evaluation of RANS turbulence models in simulating the corner separation of a high-speed compressor cascade

Large Eddy Simulation of a Controlled Diffusion Compressor Cascade

Large eddy simulation of a compressor cascade and the influence of spanwise domain

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