Engineering Applications of Computational Fluid Mechanics

In this article, single-phase, computational-fluid-dynamics simulations of free-surface vortices are presented. The purpose of the simulations is to determine the appropriate turbulence model for free-surface vortices, which could later be applied to simulations of flow in various engineering systems. The water flow in the laboratory model of a free-surface vortex was numerically simulated by unsteady single-phase computations. The vortex circumferential velocity, the downward velocity inside the vortex core and the predicted length of the free-surface vortex gas core were compared with available measurements. For the two-equation turbulence models, the results indicated the importance of the curvature correction (CC). The effect of the time-step size and the choice of the advection scheme were analyzed. For the tested case, it was determined that the unsteadiness of the flow was insufficient for the correct behavior of the scale-adaptive simulation (SAS) turbulence model. With the CC option, the shear-stress-transport (SST-CC) turbulence model and the SAS-CC turbulence model can both be used for such predictions; however, the SAS-CC model was found to be more reliable. Single-phase simulations successfully predicted the gas-core length for vortices with a short gas core. However, for long cores, the length was under-

[1]  J. Burgers.  A mathematical model illustrating the theory of turbulence , 1948 .

[2]  P. Bradshaw.  Effects of Streamline Curvature on Turbulent Flow. , 1973 .

[3]  C. H. Priddin,et al.  The calculation of turbulent boundary layers on spinning and curved surfaces , 1977 .

[4]  P. Moin,et al.  Eddies, streams, and convergence zones in turbulent flows , 1988 .

[5]  Timothy J. Barth,et al.  The design and application of upwind schemes on unstructured meshes , 1989 .

[6]  M. S. Chong,et al.  A general classification of three-dimensional flow fields , 1990 .

[7]  S. Orszag,et al.  Development of turbulence models for shear flows by a double expansion technique , 1992 .

[8]  Jinhee Jeong,et al.  On the identification of a vortex , 1995, Journal of Fluid Mechanics.

[9]  V. C. Patel,et al.  Longitudinal curvature effects in turbulent boundary layers , 1997 .

[10]  P. Spalart,et al.  On the sensitization of turbulence models to rotation and curvature , 1997 .

[11]  V. C. Patel,et al.  Experimental validation of numerical model of flow in pump-intake bays , 1999 .

[12]  Paul A. Durbin,et al.  Modeling rotational effects in eddy-viscosity closures , 1999 .

[13]  S. Balachandar,et al.  Mechanisms for generating coherent packets of hairpin vortices in channel flow , 1999, Journal of Fluid Mechanics.

[14]  P. Spalart,et al.  Turbulence Modeling in Rotating and Curved Channels: Assessing the Spalart-Shur Correction , 2000 .

[15]  M. Strelets.  Detached eddy simulation of massively separated flows , 2001 .

[16]  Matahel Ansar,et al.  Numerical simulations of inviscid three-dimensional flows at single- and dual-pump intakes , 2002 .

[17]  F. Menter,et al.  Ten Years of Industrial Experience with the SST Turbulence Model , 2003 .

[18]  Guillaume Dufour,et al.  Two-equation modeling of turbulent rotating flows , 2005 .

[19]  Marcel Lesieur,et al.  Large-Eddy Simulations of Turbulence , 2005 .

[20]  Tomoyoshi Okamura,et al.  CFD SIMULATION OF FLOW IN MODEL PUMP SUMPS FOR DETECTION OF VORTICES , 2005 .

[21]  V. Kolár,et al.  Vortex identification: New requirements and limitations , 2007 .

[22]  Y. Stepanyants,et al.  Stationary bathtub vortices and a critical regime of liquid discharge , 2008, Journal of Fluid Mechanics.

[23]  F. Menter,et al.  Development and Application of SST-SAS Turbulence Model in the DESIDER Project , 2008 .

[24]  Hong-xun Chen,et al.  Experimental and Numerical Investigation of Free Surface Vortex , 2008 .

[25]  Hideaki Monji,et al.  Proposal of Design Criteria for Gas Entrainment from Vortex Dimples Based on a Computational Fluid Dynamics Method , 2008 .

[26]  H. Kamide,et al.  Experimental Study on Gas Entrainment at Free Surface in Reactor Vessel of a Compact Sodium-Cooled Fast Reactor , 2008 .

[27]  H. Kamide,et al.  Effect of Experimental Conditions on Gas Core Length and Downward Velocity of Free Surface Vortex in Cylindrical Vessel , 2008 .

[28]  Florian R. Menter,et al.  Sensitization of the SST Turbulence Model to Rotation and Curvature by Applying the Spalart–Shur Correction Term , 2009 .

[29]  E. Merzari,et al.  Numerical Simulation of Free-Surface Vortices , 2009 .

[30]  Takumi KAWAMURA,et al.  Formulations and Validations of a High-Precision Volume-of-Fluid Algorithm on Nonorthogonal Meshes for Numerical Simulations of Gas Entrainment Phenomena , 2009 .

[31]  D. Keith Walters,et al.  A simple and robust linear eddy‐viscosity formulation for curved and rotating flows , 2009 .

[32]  H. Kamide,et al.  Effect of Experimental Conditions on Gas Core Length and Downward Velocity of Free Surface Vortex in Cylindrical Vessel , 2010 .

[33]  H. Ohshima,et al.  Improvement of Gas Entrainment Prediction Method—Introduction of Surface Tension Effect— , 2010 .

[34]  Jure Ravnik,et al.  Turbulence model comparison for a surface vortex simulation , 2010 .

[35]  Florian R. Menter,et al.  The Scale-Adaptive Simulation Method for Unsteady Turbulent Flow Predictions. Part 1: Theory and Model Description , 2010 .

[36]  Florian R. Menter,et al.  Scale-Adaptive Simulation with Artificial Forcing , 2010 .

[37]  Sergio Galván,et al.  Assessment Study of K-ɛ Turbulence Models and Near-Wall Modeling for Steady State Swirling Flow Analysis in Draft Tube Using Fluent , 2011 .

[38]  Jure Ravnik,et al.  Choice of a turbulence model for pump intakes , 2011 .

[39]  A. W. Patwardhan,et al.  Numerical and experimental investigation of onset of gas entrainment phenomenon , 2012 .

[40]  P. Chellapandi,et al.  Numerical simulation of liquid fall induced gas entrainment and its mitigation , 2013 .