CFD Calculation of Turbulent Flow with Arbitrary Wall Roughness

Apsley, David

doi:10.1007/s10494-006-9059-x

Cited by 45 publications

(17 citation statements)

References 10 publications

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“…Fig. 6 shows a comparison between non-dimensional velocity profiles of smooth and rough flat plates, including smooth, transitionally rough (k s ¼ 50 mm) and fully rough (k s ¼ 600 mm) regimes, and the analytical data [37]. As can be seen in this figure, the results of the roughness model are in good agreement with the analytical data of literature [37].…”

Section: Validation Of Roughness Model; Flow Over a Flat Platesupporting

confidence: 67%

Effects of surface roughness on deviation angle and performance losses in wet steam turbines

Esfe

Kermani

Saffar‐Avval

2015

Applied Thermal Engineering

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Section: Validation Of Roughness Model; Flow Over a Flat Platesupporting

confidence: 67%

Effects of surface roughness on deviation angle and performance losses in wet steam turbines

Esfe

Kermani

Saffar‐Avval

2015

Applied Thermal Engineering

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“…For the unsteady and non-uniform flow generally the scalable wall function Y+ value should not be more than 15 [20]. Therefore in this simulation work the value of Y+ scalable wall function is maintained as 10.06 which is reasonable for all real flow boundary conditions.…”

Section: Rotor Flow Blockage Turbulence Modelmentioning

confidence: 97%

“…To find out distortion effect under the transonic flow condition on the compressor stage the eddy-viscosity RANS two equation k-e model was used. The theory of scalable wall function methodology [20]was considered in the analysis. According to the analytical scalable wall function approach an improved turbulent velocity scale ̃is used.…”

Section: Rotor Flow Blockage Turbulence Modelmentioning

confidence: 99%

Flow blockage in a transonic axial flow compressor: simulation analysis under distorted conditions

Srinivas

Raghunandana

Shenoy

2018

IJET

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Today the aircraft industry is looking for faster and safer engines for both civil and military applications. The performance of all different types of air breathing engines depends on the amount of mass flow rate of air entering and hot gas ejecting out from the engine. Thrust is the key role for any engine performance. To achieve more thrust all the turbo machinery components like axial fan, axial flow compressor and axial flow turbine should function effectively. This paper is primarily dealing about one of the turbo machinery component, axial flow compressor performance where the study is more focused on flow blockage formation under distorted phenomena. The complete blade boundary layer formation and related flow numerical theory are discussed in detail, accordingly the boundary conditions were set to have better numerical simulations using ANSYS tool. To find the flow blockage formation suitable turbulence model was coded using the well know compressible equations. The flow blockage between the rotor and stator of the compressor stage was calculated and also validated with that of experimental data effectively. The flow simulation results also revealed that the performance parameters under the modern engine transonic speed from Mach 0.8 to 1.2 under the distorted conditions are better for aeromechanical features.

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“…CFD numerical calculation module can be used to simulate the laminar and turbulent flows of Newtonian and non-Newtonian fluids in hydraulics. Thakur et al [29] used CFD simulations to study the influence of the size of Newtonian and non-Newtonian fluids on their flow fields and power consumption, Aubin et al [30] modeled and analyzed turbulence in a stirred tank based on a CFD model, and Apsley et al [31] used a CFD model to study the effects of roughness on turbulent flow. ANSYS FLUENT 19.1 (ANSYS, Canonsburg, PA, USA) was employed to construct a CFD model to simulate the characteristics of flow in fractures in this study.…”

Section: Numeric Simulation Modelmentioning

confidence: 99%

A Fast Calculation Model for Local Head Loss of Non-Darcian Flow in Flexural Crack

Liu

Mou

Song

et al. 2020

Water

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Local head loss caused by fracture intersection is often ignored because there has not been a simple method to calculate it until now. Relevant research shows that neglecting the local flow resistance leads to inaccurate results, especially when the velocity and cross angle are large. Therefore, it is necessary to find a portable method for calculation. Physical experiments of single fracture with different apertures (e = 0.77, 1.18, 1.97, 2.73 mm) were set up first to study the flow characteristics, showing obvious non-Darcian flow, which can be depicted by the Forchheimer equation when the flow velocity is sufficiently large. The computational fluid dynamics (CFD) software ANSYS FLUENT was used to build numeric simulation models. A good correlation between CFD simulation results and physical experiment results was found (Pearson's correlation coefficient > 0.99). Then, the CFD models of flexural crack with different angles from 30 • to 150 • were established to compute the pressure drop of flexural crack at different velocity. It was found that the local head loss of the flexural crack varied with the bending angle, and its coefficient was expressed by the deformation of the logistic equation. By using this model, as well as a frictional head loss equation fitted by Forchheimer equation, the head loss of crossed fissures with fixed fracture aperture could be easily calculated. Water 2020, 12, 232 2 of 15 applications, a quadratic equation (J = Av + Bv 2 ) and an exponential equation (J = Cv −m ) are used to under limited conditions [8-11]. The Forchheimer equation can express the characteristics of non-Darcian flow in fracture [12-15]: − ∇P = aQ + bQ 2 (1) where Q is volumetric flow velocity, a and b are model coefficients, and −∇P is the pressure gradient. The factors affecting the flow of fissure fluid are complex and include the shape of the fissure, degree of contact, roughness, fluid viscosity, and external pressure [16-19]. Liu et al. [20] studied the law of fluid movement in a fracture network and found that the coefficient (a, b) of the Forchheimer equation decreases with an increase in the fracture aperture, and the error in model fitting can be reduced by expressing the coefficients of the Forchheimer equation as a power equation of fracture aperture [14]. Olson et al. [21] studied the effect of the ratio of the fracture opening to its height on the flow pattern, and Shu et al. [22] studied the variation in head loss with the width of the fissure and the velocity of flow when water flows through L-shaped fissures. Li et al. [23] studied the correlation between the head loss of a fluid in cross fissures and the width as well as roughness of the fissures.This study proposes a portable calculation model where the aperture and the shape of flexural crack are considered to predict head loss directly. It is difficult to consider all factors when studying the characteristics of flow in fractures. In order to investigate the influence of each one, the synergistic effects of each condition need to be reduced, ...

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CFD Calculation of Turbulent Flow with Arbitrary Wall Roughness

Cited by 45 publications

References 10 publications

Effects of surface roughness on deviation angle and performance losses in wet steam turbines

Effects of surface roughness on deviation angle and performance losses in wet steam turbines

Flow blockage in a transonic axial flow compressor: simulation analysis under distorted conditions

A Fast Calculation Model for Local Head Loss of Non-Darcian Flow in Flexural Crack

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