Turbulence Models Performance Assessment for Pressure Prediction during Cylinder Water Entry

2012 ◽  
Vol 224 ◽  
pp. 225-229 ◽  
Author(s):  
Bao Dong Guo ◽  
Pei Qing Liu ◽  
Qiu Lin Qu ◽  
Yue Li Cui
Keyword(s):  
Stokes Equations ◽  
Turbulence Models ◽  
Water Entry ◽  
Navier Stokes ◽  
Engineering Practice ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Dynamic Mesh Technique ◽  
Volume Method ◽  
Mesh Technique

Numerical simulations of two-dimensional cylinder free droping into water are presented based on volume of fluid (VOF) method and dynamic mesh technique. Solutions with a time-accurate finite-volume method (FVM) were generated based on the unsteady compressible ensemble averaged Navier-Stokes equations for the air and the unsteady incompressible ensemble averaged Navier-Stokes equations for the water. Computed pressure histories of the cylinder were compared with experimentally measured values. The performance of various turbulence models for pressure prediction was assessed. The results indicate that Realizable k-epsilon model with Enhanced Wall Treatment is the best choice for engineering practice.

A Hybrid Unstructured/Spectral Method for the Resolution of Navier-Stokes Equations

2009 ◽  
Author(s):  
Roque Corral ◽  
Javier Crespo
Keyword(s):  
Finite Volume Method ◽  
Finite Volume ◽  
Stokes Equations ◽  
High Order ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
The Third ◽  
Third Dimension ◽  
Volume Method

A novel high-order finite volume method for the resolution of the Navier-Stokes equations is presented. The approach combines a third order finite volume method in an unstructured two-dimensional grid, with a spectral approximation in the third dimension. The method is suitable for the resolution of complex two-dimensional geometries that require the third dimension to capture three-dimensional non-linear unsteady effects, such as those for instance present in linear cascades with separated bubbles. Its main advantage is the reduction in the computational cost, for a given accuracy, with respect standard finite volume methods due to the inexpensive high-order discretization that may be obtained in the third direction using fast Fourier transforms. The method has been applied to the resolution of transitional bubbles in flat plates with adverse pressure gradients and realistic two-dimensional airfoils.

Effect of the turbulence models on Rushton turbine generated flow in a stirred vessel

2011 ◽  
Vol 1 (4) ◽  
Author(s):  
Wajdi Chtourou ◽  
Meriem Ammar ◽  
Zied Driss ◽  
Mohamed Abid
Keyword(s):  
Dissipation Rate ◽  
Stokes Equations ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Stirred Vessel ◽  
Rushton Turbine ◽  
Numerical Predictions ◽  
Volume Method

AbstractIn this paper, we performed a comparison of four turbulence models using for numerical simulation of the hydrodynamic structure generated by a Rushton turbine in a cylindrical tank. The finite volume method was employed to solve the Navier-Stokes equations governing the transport of momentum. In this study four closure models tested were: k-ɛ standard, k-ɛ RNG, k-ɛ Realizable and RSM (Reynolds Stress Model). MRF (Multi Reference Frame) technique was used with FLUENT software package. The present work aimed to provide improved predictions of turbulent flow in a stirred vessel and in particular to assess the ability to predict the dissipation rate of turbulent kinetic energy (e) that constitutes a most stringent test of prediction capability due to the small scales at which dissipation takes place. The amplitude of local and overall dissipation rate is shown to be strongly dependent on the choice of turbulence model. The numerical predictions were compared with literature results for comparable configurations and with experimental data obtained using Particle Image Velocimetry (PIV). A very good agreement was found with regards to turbulence.

scholarly journals Viscous Flow Calculations in Turbomachinery Channels

1989 ◽  
Author(s):  
Francesco Martelli ◽  
Vittorio Michelassi
Keyword(s):  
Stokes Equations ◽  
Turbulent Viscosity ◽  
Axisymmetric Flow ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Algebraic Expression ◽  
Two Dimensional ◽  
Approximate Factorization ◽  
Navier Stokes Equations ◽  
Flow Configurations

An implicit procedure based on the artificial compressibility formulation is presented for the numerical solution of the two-dimensional incompressible steady Navier-Stokes equations in the presence of large separated regions. Turbulence effects are accounted for by the Chien low Reynolds number form of the K-ε turbulence model and the Baldwin-Lomax algebraic expression for turbulent viscosity. The governing equations are written in conservative form and implicitly solved in fully coupled form using the approximate factorization technique. Preliminary tests were carried out in a laminar flow regime to check the accuracy and stability of the method in two-dimensional and cylindrical axisymmetric flow configurations. After testing in laminar and turbulent flow regimes and comparing the two turbulence models, the code was successfully applied to an actual gas turbine diffuser at low Mach numbers.

scholarly journals A Numerical Study of Wind Flow Over a Coal Storage Shelter

10.14311/1692 ◽  
2012 ◽  
Vol 52 (6) ◽  
Author(s):  
Tomáš Bodnár ◽  
Ludek Beneš ◽  
Luboš Pirkl ◽  
Eva Gulíková
Keyword(s):  
Flow Model ◽  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Wind Flow ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Structured Grid ◽  
Impermeable Wall ◽  
Volume Method

This paper presents some of the main numerical results obtained while simulating the wind flow over a shelter covering a coal storage. The aim of this numerical study was to evaluate the change in flow patterns caused by adding an impermeable wall to the originally open shelter. The numerical simulations of selected two-dimensional cases were performed using an open-source CFD code. The flow model is based on Reynolds-Averaged Navier-Stokes Equations solved using a finite-volume method on a structured grid. The turbulence is parametrized using the standard k − ε model. Two shelter wall configuration variants are evaluated, and are compared with the original open shelter setup.

scholarly journals A solution of two-dimensional magnetohydrodynamic flow using the finite volume method

2014 ◽  
Vol 11 (2) ◽  
pp. 201-211
Author(s):  
Sonia Naceur ◽  
Fatima Kadid ◽  
Rachid Abdessemed
Keyword(s):  
Finite Volume Method ◽  
Finite Volume ◽  
Stokes Equations ◽  
Transport Equations ◽  
Navier Stokes ◽  
Magnetic Vector Potential ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Fluent Software ◽  
Volume Method

This paper presents the two dimensional numerical modeling of the coupling electromagnetic-hydrodynamic phenomena in a conduction MHD pump using the Finite volume Method. Magnetohydrodynamic problems are, thus, interdisciplinary and coupled, since the effect of the velocity field appears in the magnetic transport equations, and the interaction between the electric current and the magnetic field appears in the momentum transport equations. The resolution of the Maxwell's and Navier Stokes equations is obtained by introducing the magnetic vector potential A, the vorticity z and the stream function y. The flux density, the electromagnetic force, and the velocity are graphically presented. Also, the simulation results agree with those obtained by Ansys Workbench Fluent software.

scholarly journals Dynamics of Single Droplet Splashing on Liquid Film by Coupling FVM with VOF

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 841
Author(s):  
Yuzhen Jin ◽  
Huang Zhou ◽  
Linhang Zhu ◽  
Zeqing Li
Keyword(s):  
Liquid Film ◽  
Weber Number ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Single Droplet ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
The Relationship

A three-dimensional numerical study of a single droplet splashing vertically on a liquid film is presented. The numerical method is based on the finite volume method (FVM) of Navier–Stokes equations coupled with the volume of fluid (VOF) method, and the adaptive local mesh refinement technology is adopted. It enables the liquid–gas interface to be tracked more accurately, and to be less computationally expensive. The relationship between the diameter of the free rim, the height of the crown with different numbers of collision Weber, and the thickness of the liquid film is explored. The results indicate that the crown height increases as the Weber number increases, and the diameter of the crown rim is inversely proportional to the collision Weber number. It can also be concluded that the dimensionless height of the crown decreases with the increase in the thickness of the dimensionless liquid film, which has little effect on the diameter of the crown rim during its growth.

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