Numerical Simulation of Three-Dimensional Complex Flows Using a Pressure-Based Non-Staggered Grid Method

1996 ◽  
pp. 372-378
Author(s):  
K. Yakinthos ◽  
M. Ballas ◽  
P. Tamamidis ◽  
A. Goulas
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Grid Method ◽  
Staggered Grid ◽  
Complex Flows

Numerical Simulation of Two-Phase Sloshing Flow in LNG Tank Using Finite-Analytic Level-Set Method

2007 ◽  
Author(s):  
Kai Yu ◽  
Hamn-Ching Chen ◽  
Jang Whan Kim ◽  
Young-Bum Lee
Keyword(s):  
Numerical Simulation ◽  
Wave Breaking ◽  
Impact Load ◽  
Three Dimensional ◽  
Impact Pressure ◽  
Staggered Grid ◽  
Two Phase ◽  
Local Flow ◽  
Hull Structure ◽  
Lng Tank

Impact pressure due to sloshing is of great concern for the ship owners, designers and builders of the LNG carriers regarding the safety of LNG containment system and hull structure. Sloshing of LNG in a partially filled tank has been an active area of research with numerous experimental and numerical investigations over the past decade. In order to accurately predict the sloshing impact load, it is necessary to develop advanced numerical simulation tools which can provide accurate resolution of local flow phenomena including wave breaking, jet formation, gas entrapping and liquid-gas interactions. In the present study, a new numerical method is developed for the simulation of violent sloshing flow inside a three-dimensional LNG tank considering wave breaking and liquid-gas interaction. The sloshing flow inside a membrane-type LNG tank is simulated numerically using the Finite-Analytic Navier-Stokes (FANS) method. The governing equations for two-phase air and water flows are formulated in curvilinear coordinate system and discretized using the finite-analytic method on a non-staggered grid. Simulations were performed for LNG tank in transverse and longitudinal motions including horizontal, vertical, and rotational motions. The predicted impact pressures were compared with the corresponding experimental data. The validation results clearly illustrate the capability of the present two-phase FANS method for accurate prediction of impact pressure in sloshing LNG tank including violent free surface motion, three-dimensional instability and air trapping effects.

Three-dimensional direct numerical simulation of a turbulent lifted hydrogen jet flame in heated coflow: a chemical explosive mode analysis

2010 ◽  
Vol 652 ◽  
pp. 45-64 ◽  
Author(s):  
T. F. LU ◽  
C. S. YOO ◽  
J. H. CHEN ◽  
C. K. LAW
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Near Field ◽  
Three Dimensional ◽  
Mode Analysis ◽  
Scalar Dissipation ◽  
Complex Flows ◽  
Jet Flame ◽  
Auto Ignition ◽  
Grid Points

A chemical explosive mode analysis (CEMA) was developed as a new diagnostic to identify flame and ignition structure in complex flows. CEMA was then used to analyse the near-field structure of the stabilization region of a turbulent lifted hydrogen–air slot jet flame in a heated air coflow computed with three-dimensional direct numerical simulation. The simulation was performed with a detailed hydrogen–air mechanism and mixture-averaged transport properties at a jet Reynolds number of 11000 with over 900 million grid points. Explosive chemical modes and their characteristic time scales, as well as the species involved, were identified from the Jacobian matrix of the chemical source terms for species and temperature. An explosion index was defined for explosive modes, indicating the contribution of species and temperature in the explosion process. Radical and thermal runaway can consequently be distinguished. CEMA of the lifted flame shows the existence of two premixed flame fronts, which are difficult to detect with conventional methods. The upstream fork preceding the two flame fronts thereby identifies the stabilization point. A Damköhler number was defined based on the time scale of the chemical explosive mode and the local instantaneous scalar dissipation rate to highlight the role of auto-ignition in affecting the stabilization points in the lifted jet flame.

Two-Component Incompressible Fluid Model for Simulating the Cohesive Soil Erosion

2015 ◽  
Vol 725-726 ◽  
pp. 361-368 ◽  
Author(s):  
Yuri Zakharov ◽  
Anton Zimin ◽  
Igor Nudner ◽  
Vladimir Ragulin
Keyword(s):  
Soil Erosion ◽  
Stokes Equations ◽  
Variable Viscosity ◽  
Fluid Model ◽  
Three Dimensional ◽  
Grid Method ◽  
Cohesive Soil ◽  
Staggered Grid ◽  
Physical Factors ◽  
Inhomogeneous System

Non-stationary inhomogeneous system of the Navier–Stokes equations with variable viscosity depending on the density has been used for modeling the process of the cohesive soil erosion. Value of the density has been determined by the convection–diffusion equation. For solving the obtained system we have used an algorithm consisting of the splitting scheme on physical factors and the predictor–corrector method. The system has been solved on the staggered grid by the grid method. The results of calculations for two-dimensional and three-dimensional problems are presented.

Three-dimensional numerical simulation of viscoelastic flow through an abrupt contraction geometry

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Young Il Kwon ◽  
Dongjin Seo ◽  
Jae Ryoun Youn
Keyword(s):  
Finite Volume Method ◽  
Finite Volume ◽  
Interpolation Method ◽  
Three Dimensional ◽  
Grid Method ◽  
Viscoelastic Flow ◽  
Staggered Grid ◽  
Algebraic Equations ◽  
Accelerate Convergence ◽  
Volume Method

AbstractA numerical scheme for simulating three-dimensional viscoelastic flow was developed. The three-dimensional finite volume method (FVM) based on a non-staggered grid and the semi-implicit method for pressure-linked equations (SIMPLE) were adopted to solve the continuity and momentum equations. As we used a non-staggered grid, the momentum interpolation method (MIM) was employed to avoid checkerboard type pressure fields. Viscoelastic properties of the fluid were described by the Phan-Thien and Tanner (PTT) model, which was treated by the compressive interface capturing scheme for arbitrary meshes (CICSAM). The elastic viscous split stress scheme (EVSS) was used to decouple the velocity and the stress fields. Algebraic equations obtained by the above schemes were handled by an iterative solver and a multi-grid method was applied to accelerate convergence. In order to verify the scheme developed in this study, Newtonian flow in a rectangular duct was studied and the resulting velocity fields were compared with the analytical flow fields. Then viscoelastic flow in 4:1 contraction geometry, one of the most frequently used benchmarking problems, was predicted by applying the fully three-dimensional finite volume method.

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