Simulating Flow Over Circular Spillways by Using Different Turbulence Models

Rahimzadeh, Hassan; Maghsoodi, Reza; Sarkardeh, Hamed; Tavakkol, Sasan

doi:10.1080/19942060.2012.11015406

Cited by 31 publications

(21 citation statements)

References 13 publications

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“…The LRR (Launder-Reece-Rodi) model is one of the variants of the Reynolds Stress Models (RSM) (Greenshields, 2018). It avoids the eddy viscosity approach and determines the turbulent stresses directly by solving six transport equations attained by performing algebra on time-averaged and instantaneous Navier-Stokes equations (Hekmatzadeh, Papari, & Amiri, 2018;Rahimzadeh, Maghsoodi, Sarkardeh, & Tavakkol, 2012).…”

Section: Turbulence Modelsmentioning

confidence: 99%

Numerical simulation of flow over ogee crested spillways under high hydraulic head ratio

Imanian

Mohammadian

2019

Engineering Applications of Computational Fluid Mechanics

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Ogee spillway is one of the most common types of the spillway. Researchers have attempted to investigate the hydraulics of ogee structure under hydraulic heads near the design head. Herein, an ogee-crested spillway is studied at heads significantly greater than the design head. The efforts are undertaken to study the hydrodynamic field under high head ratio conditions by conducting a numerical simulation using OpenFOAM with five turbulence closures including standard k-, realizable k-, RNG k-, k-ω SST and LRR. The comparisons of flow parameters under different head ratios with the experimental data demonstrated that the LRR model had the best performance, which shows its strength in cases dealing with flow separation or significant streamline curvature. It is found that with increasing hydraulic head, up to seven times that of the design head, the flow separation zone grows linearly. Discharge coefficients are studied for a wide range of head ratios. It is concluded that increasing head ratio up to five leads to an increase in the discharge coefficient due to decreasing pressure on the ogee crest. As head ratio increases to greater values, the discharge coefficient drops suddenly due to some changes in the pressure field.

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Section: Turbulence Modelsmentioning

confidence: 99%

Numerical simulation of flow over ogee crested spillways under high hydraulic head ratio

Imanian

Mohammadian

2019

Engineering Applications of Computational Fluid Mechanics

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“…grid was adopted, and the elbow part has an encryption treatment as depicted in Figure 2(b). According to the requirements of the wall function, the value of y+ should not be more than 1, as suggested in some studies (Keller, 1978;Rahimzadeh, Maghsoodi, Sarkardeh, & Tavakkol, 2014). Thus, the height of the first layer in the vicinity of the wall was set to 0.1 mm, and the stretching ratio was specified as 1.2.…”

Section: Geometric Structures and Fluid Parametersmentioning

confidence: 99%

Numerical study of the hydrodynamic parameters influencing internal corrosion in pipelines for different elbow flow configurations

Liu

Gong

Zhang

et al. 2019

Engineering Applications of Computational Fluid Mechanics

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Oil-water two-phase flow is common in the ocean engineering, petroleum, and chemical industries, among others. In the transportation process, the elbow system-as a paramount component-usually suffers from internal corrosion. In order to investigate the corrosion-prone characteristics of elbow systems, the volume of fluid (VOF) method and the renormalization group (RNG) kmodel were used to study the oil-water flow in three different elbow configurations. The results indicate that the maximum wall shear stress and mass transfer coefficient are located at the intrados of the elbow for all flow configurations. Nevertheless, for horizontal-upward and horizontal-horizontal elbow flows, water does not come into direct contact with the intrados of the elbow, meaning it is much less susceptible to corrosion. Thus, a multiparameter model which also takes into account the water-volume fraction is necessary for characterizing the corrosion process. When this was combined with an analysis of the water wetting process, the horizontal-downward elbow flow was found to exhibit the largest corrosion risk among the three configurations examined, the horizontal-upward elbow flow was the least susceptible and the horizontal-horizontal elbow flow was in the middle.

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“…The VOF Model is sometimes used to simulate aerator flows (Zhang, JM, Chen JG, Xu WL., 2011; Deng, J., Xu, W. L., Lei, J., and Diao, M. J., 2005; Jothiprakash, V. Y., Bhosekar, V. V., and Deolaikar, P. B., 2015; Liu, T., and Yang, J., 2014); Kökpınar, M. A., and Göğüş, M., 2002; some researchers employ the Mixture Model to study an aerator flow and found that the model is more suitable for simulating aerator flows and especially in high air-concentration regions (Rahimzadeh,H., Maghsoodi, R., Sarkardeh, H., and Tavakkol, S., 2012;Aydin, M. C. and Ozturk, M., 2009).…”

Section: Figure 1 Flow Region Over Typical Aeratormentioning

confidence: 99%

Investigating the Effect of Aeration on the Flow Characteristics Around Under Pressure Tunnel Aerator Using Openfoam Open Source Software

Ebrahimnezhadian

Manafpour

2019

Journal of Applied Engineering Sciences

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The flow around the ramp embedded in a pressurized tunnel is divided into the various zones immediately downstream of the ramp, including the cavity and the main zone of flow above the shear layer. The aeration coefficient of the flow from the lower surface (inside the cavity)(βlower) is a function of non-dimensional numbers which aerator geometry parameters such as cavity length to ramp height Lc/tr is considered as one of the most important parameters. Therefore, in the present study, OpenFOAM software and RNG k-ε turbulence model were used to simulate the flow to study the aeration effect on flow characteristics, so the range of aeration coefficient as 0%<β<10% for four ramps with different tr/d ratios is Applied, then by increasing the aeration coefficient in the range of 0%<β<16%, The dependency range of relative Cavity length Lc/tr to (β) was evaluated. In order to verify performance of the numerical model, experimental results of Manafpour test were used. The results of the research indicate that in the aeration of flow with aerator ramp, the height of ramp has more influence relative to ramp angle. Moreover the main Effectiveness of the aeration coefficient on the cavity length was limited to air percent less than 10%.

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Simulating Flow Over Circular Spillways by Using Different Turbulence Models

Cited by 31 publications

References 13 publications

Numerical simulation of flow over ogee crested spillways under high hydraulic head ratio

Numerical simulation of flow over ogee crested spillways under high hydraulic head ratio

Numerical study of the hydrodynamic parameters influencing internal corrosion in pipelines for different elbow flow configurations

Investigating the Effect of Aeration on the Flow Characteristics Around Under Pressure Tunnel Aerator Using Openfoam Open Source Software

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