Three-dimensional compressible–incompressible turbulent flow simulation using a pressure-based algorithm

2008 ◽  
Vol 37 (6) ◽  
pp. 747-766 ◽  
Author(s):  
Khodayar Javadi ◽  
Masoud Darbandi ◽  
Mohammad Taeibi-Rahni
Keyword(s):  
Turbulent Flow ◽  
Three Dimensional ◽  
Flow Simulation

The Characteristics Research of Tube Vortex Based on Large Eddy Simulation

2011 ◽  
Vol 121-126 ◽  
pp. 3657-3661
Author(s):  
Dun Zhang ◽  
Yuan Zheng ◽  
Ying Zhao ◽  
Jian Jun Huang
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Complex Geometry ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Computational Method ◽  
Francis Turbine ◽  
Eddy Simulation ◽  
Large Eddy

Numerical simulation of three-dimensional transient turbulent flow in the whole flow passage of a Francis turbine were based upon the large eddy simulation(LES) technique on Smargorinsky model and sliding mesh technology. The steady flow data simulated with the standard k-εmodel was used as the initial conditions for the unsteady simulation. The results show that LES can do well transient turbulent flow simulation in a Francis turbine with complex geometry. The computational method provides some reference for exploring the mechanism of eddy formation in a complex turbulent of hydraulic machinery.

Experimental Research and Turbulent Flow Simulation of the Updraft Free-Exit-Flow Hydropower Turbine System

2002 ◽  
Author(s):  
Haifeng Li ◽  
Yulin Wu ◽  
David T. Kao
Keyword(s):  
Turbulent Flow ◽  
Experimental Research ◽  
Production Efficiency ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Predicting Performance ◽  
Optimizing Design

During development of the updraft free-exit-flow hydropower turbine system, serious attention was paid to impact of the traditional turbine system to environment. The paper presents results of experimental research and three-dimensional turbulent flow simulation of the runner. The experiment demonstrated that, on one hand, the system can enhance exit flow aeration and downstream water quality; on the other hand, it gives good results in terms of its power production efficiency, about 85%. Based on the time-averaged Navier-Stokes equations and standard k-ε model, the SIMPLEC algorithm was applied for the numerical analysis. To guarantee credibility of the calculation, FLUENT5.5 code was used, which can provide distribution of pressure and velocity respectively. With comparison between the experimental data and calculating results, it can be concluded that flow simulation can be an effective tool for predicting performance and optimizing design of new turbine runner.

Large-Eddy Turbulent Flow Simulation of an Industrial Helical Static Mixer

Volume 4 ◽  
2004 ◽  
Author(s):  
Ramin K. Rahmani ◽  
Theo G. Keith ◽  
Anahita Ayasoufi
Keyword(s):  
Turbulent Flow ◽  
Critical Role ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Reynolds Numbers ◽  
Static Mixer ◽  
Static Mixers ◽  
Large Eddy ◽  
Turbulent Models ◽  
Les Model

Viscous liquids have to be homogenized in continuous operations in many branches of processing industries; and therefore, fluid mixing plays a critical role in the success or failure of many industrial processes. Consequences of improper mixing include non-reproducible processing conditions and lowered product quality, resulting in the need for more elaborate downstream purification processes and increased waste disposal costs. The range of practical flow Reynolds numbers for helical static mixers in industry is usually from very small (Re ≈ 0) to moderate values (e.g. Re = 5,000). However, it has been found that the flow regime within helical static mixers is turbulent for relatively low Reynolds numbers, compared to the flow inside a pipe with no mixing elements present. This paper extends previous studies by the authors on the industrial helical static mixer. Its purpose is to present an improved understanding of the turbulent flow pattern for single-phase liquids through the mixer. Three-dimensional finite volume simulations are used to study the performance of the mixer using different turbulent models. Large-Eddy Simulation (LES) model is applied to the flow in an industrial helical static mixer to calculate the flow velocities, pressure drops, etc. Using a variety of predictive tools, the mixing results are obtained. Also, the accuracy and global performance of several different turbulent models are compared against the LES model.

scholarly journals Interactions between Tandem Cylinders in an Open Channel: Impact on Mean and Turbulent Flow Characteristics

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1718
Author(s):  
Hasan Zobeyer ◽  
Abul B. M. Baki ◽  
Saika Nowshin Nowrin
Keyword(s):  
Turbulent Flow ◽  
Open Channel ◽  
Recirculation Zone ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Flow Recirculation ◽  
Tandem Cylinders ◽  
Flow Development ◽  
The Mean ◽  
Recirculation Length

The flow hydrodynamics around a single cylinder differ significantly from the flow fields around two cylinders in a tandem or side-by-side arrangement. In this study, the experimental results on the mean and turbulence characteristics of flow generated by a pair of cylinders placed in tandem in an open-channel flume are presented. An acoustic Doppler velocimeter (ADV) was used to measure the instantaneous three-dimensional velocity components. This study investigated the effect of cylinder spacing at 3D, 6D, and 9D (center to center) distances on the mean and turbulent flow profiles and the distribution of near-bed shear stress behind the tandem cylinders in the plane of symmetry, where D is the cylinder diameter. The results revealed that the downstream cylinder influenced the flow development between cylinders (i.e., midstream) with 3D, 6D, and 9D spacing. However, the downstream cylinder controlled the flow recirculation length midstream for the 3D distance and showed zero interruption in the 6D and 9D distances. The peak of the turbulent metrics generally occurred near the end of the recirculation zone in all scenarios.

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