Predicting distributed roughness induced transition with a four-equation laminar kinetic energy transition model

Liu, Zaijie; Zhao, Yatian; Chen, Shusheng; Yan, Chao; Cai, Fangjie

doi:10.1016/j.ast.2020.105736

Cited by 20 publications

(7 citation statements)

References 40 publications

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“…Another interesting group of transition models uses concept of laminar kinetic energy (LKE) as first proposed by Mayle and Schultz (1997). Walters and Leylek (2004) proposed a k T -k L -ω transition model, which was later extended for supersonic flows (Qin et al, 2017) and Liu et al (2020) also attempted to model the influence of roughness.…”

Section: Transition Modelingmentioning

confidence: 99%

Modeling the influence of surface roughness on boundary layer transition

Mačák,

Fürst

2023

Engineering Mechanics

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This paper provides a summary of both history and current state-of-art in modeling of the surface roughness influence on boundary layer transition from laminar to turbulent regime. Discussed techniques are restricted to RANS models as these are nowadays still in major use in complex engineering applications. Present modeling techniques for surface roughness are critically reviewed. Finally, challenges connected with modeling of surface roughness influence are highlighted and potential ways for future work in this area are discussed.

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Section: Transition Modelingmentioning

confidence: 99%

Modeling the influence of surface roughness on boundary layer transition

Mačák,

Fürst

2023

Engineering Mechanics

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“…Two dimensional roughness can amplify the instability waves and progressively move transition forward. Discrete 3D roughness, such as cavities and protrusions, can introduce horseshoe and hairpin vortices to the flow field and cause laminar flow to become turbulence [30]. Surface roughness leads to an increase in turbulence production near the wall, which further enhances the wall shear stress and heat transfer [31].…”

Section: Roughness Modellingmentioning

confidence: 99%

Blade Roughness Effects on Compressor and Engine Performance—A CFD and Thermodynamic Study

Alqallaf

Teixeira

2021

Aerospace

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Degradation of compressors is a common concern for operators of gas turbine engines (GTEs). Surface roughness, due to erosion or fouling, is considered one of the major factors of the degradation phenomenon in compressors that can negatively affect the designed pressure rise, efficiency, and, therefore, the engine aero/thermodynamic performance. The understanding of the aerodynamic implications of varying the blade surface roughness plays a significant role in establishing the magnitude of performance degradation. The present work investigates the implications due to the degradation of the compressor caused by the operation in eroding environments on the gas turbine cycle performance linking, thereby, the compressor aerodynamics with a thermodynamic cycle. At the core of the present study is the numerical assessment of the effect of surface roughness on compressor performance employing the Computational Fluid Dynamics (CFD) tools. The research engine test case employed in the study comprised a fan, bypass, and two stages of the low pressure compressor (booster). Three operating conditions on the 100% speed-line, including the design point, were investigated. Five roughness cases, in addition to the smooth case, with equivalent sand-grain roughness (ks) of 15, 30, 45, 60, and 150 µm were simulated. Turbomatch the Cranfield in-house gas turbine performance simulation software, was employed to model the degraded engine performance. The study showed that the increase in the uniform roughness is associated with sizable drops in efficiency, booster pressure ratio (PR), non-dimensional mass flow (NDMF), and overall engine pressure ratio (EPR) together with rises in turbine entry temperature (TET) and specific fuel consumption (SFC). The performance degradation evaluation employed variables such as isentropic efficiency (ηis), low pressure compressor (LPC) PR, NDMF, TET, SFC, andEPR. The variation in these quantities showed, for the maximum blade surface degradation case, drops of 7.68%, 2.62% and 3.53%, rises of 1.14% and 0.69%, and a drop of 0.86%, respectively.

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“…The roughness height, h s , was about 3.3μm. The attack angle is set to 15° and the Reynolds number based on the long diameter is set to 6.5×10 6 . The flow was nearly incompressible and the Mach number is set to 0.2.…”

Section: Dns Calibrationmentioning

confidence: 99%

“…Liu et al [6] employed an additional transport equation of A r , the roughness amplification factor, to reflect roughness effect in transition process. Liu et al [6] also employed the Wilcox wall boundary condition for ω [7] to introduce roughness effect in turbulent region.…”

Section: Introductionmentioning

confidence: 99%

“…Xiang et al [5] proposed a hypersonic cross-flow transition criterion considering surface roughness, yet no roughness modeling for fully developed turbulence was presented. Liu et al [6] employed an additional transport equation of A r , the roughness amplification factor, to reflect roughness effect in transition process. Liu et al [6] also employed the Wilcox wall boundary condition for ω [7] to introduce roughness effect in turbulent region.…”

Section: Introductionmentioning

confidence: 99%

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Extension of the KDO Turbulence/Transition Model to Account for Roughness

Fang

2021

Preprint

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Wall roughness significantly influences both laminar-turbulent transition process and fully developed turbulence. This work has developed a wall roughness extension for the KDO turbulence/transition model. The roughness effect is introduced via the modification of the k and νt boundary conditions, i.e., the wall is considered to be raised at an extra height. The equivalent roughness height is linked to the actual roughness height, and the ratio between them is determined by reasoning. With such a roughness extension, the predictions of the KDO RANS model agree well with the measurements of turbulent boundary layer with a sand grain surface, while the KDO transition model yields accurate cross-flow transition predictions of flow past a 6:1 spheroid.

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Predicting distributed roughness induced transition with a four-equation laminar kinetic energy transition model

Cited by 20 publications

References 40 publications

Modeling the influence of surface roughness on boundary layer transition

Modeling the influence of surface roughness on boundary layer transition

Blade Roughness Effects on Compressor and Engine Performance—A CFD and Thermodynamic Study

Extension of the KDO Turbulence/Transition Model to Account for Roughness

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