scholarly journals Simulation of Partial and Supercavitating Flows around Axisymmetric and Quasi-3D Bodies by Boundary Element Method Using Simple and Reentrant Jet Models at the Closure Zone of Cavity

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
M. Nouroozi ◽  
M. Pasandidehfard ◽  
M. H. Djavareshkian
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Numerical Solutions ◽  
Stokes Equations ◽  
Simple Algorithm ◽  
Navier Stokes ◽  
Cavitating Flows ◽  
Navier Stokes Equations ◽  
Short Time ◽  
Element Method

A fixed-length Boundary Element Method (BEM) is used to investigate the super- and partial cavitating flows around various axisymmetric bodies using simple and reentrant jet models at the closure zone of cavity. Also, a simple algorithm is proposed to model the quasi-3D cavitating flows over elliptical-head bodies using the axisymmetric method. Cavity and reentrant jet lengths are the inputs of the problem and the cavity shape and cavitation number are some of the outputs of this simulation. A numerical modeling based on Navier-Stokes equations using commercial CFD code (Fluent) is performed to evaluate the BEM results (in 2D and 3D cases). The cavitation properties approximated by the present research study (especially with the reentrant jet model) are very close to the results of other experimental and numerical solutions. The need for a very short time (only a few minutes) to reach the desirable convergence and relatively good accuracy are the main advantages of this method.

Solution of 3D Velocity-Vorticity Formulation of the Navier-Stokes Equations by Boundary Element Method

2007 ◽  
Author(s):  
Jure Ravnik ◽  
Leopold Škerget ◽  
Zoran Žunič ◽  
Theodore E. Simos ◽  
George Psihoyios ◽  
...  
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Element Method

scholarly journals A Numerical Model of an Acoustic Metamaterial Using the Boundary Element Method Including Viscous and Thermal Losses

2017 ◽  
Vol 25 (04) ◽  
pp. 1750006 ◽  
Author(s):  
V. Cutanda Henríquez ◽  
P. Risby Andersen ◽  
J. Søndergaard Jensen ◽  
P. Møller Juhl ◽  
J. Sánchez-Dehesa
Keyword(s):  
Finite Element Method ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Numerical Implementation ◽  
Navier Stokes Equations ◽  
Acoustic Metamaterial ◽  
Acoustic Losses ◽  
Element Method

In recent years, boundary element method (BEM) and finite element method (FEM) implementations of acoustics in fluids with viscous and thermal losses have been developed. They are based on the linearized Navier–Stokes equations with no flow. In this paper, such models with acoustic losses are applied to an acoustic metamaterial. Metamaterials are structures formed by smaller, usually periodic, units showing remarkable physical properties when observed as a whole. Acoustic losses are relevant in metamaterials in the millimeter scale. In addition, their geometry is intricate and challenging for numerical implementation. The results are compared with existing measurements.

scholarly journals THE APPLICATION OF THE BOUNDARY ELEMENT METHOD TO SOLVE VISCOUS FLOW PROBLEMS BASED ON PRIMITIVE VARIABLES FORMULATION

2004 ◽  
Vol 3 (1) ◽  
Author(s):  
M. F. C. L. Santos ◽  
J. R. Barbosa ◽  
H. F. F. M. Carneiro
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Stokes Equations ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Driven Cavity ◽  
Low Reynolds Numbers ◽  
Flow Problems ◽  
Element Method

The boundary element method is applied to the solution of incompressible fluid flow problems governed by the continuity and Navier-Stokes equations. The differential equations are transformed into integral equations. Indication of the transformation is given in detail. Application to simple flow cases such as the driven cavity and forward facing step is presented. Convergence difficulties are indicated, which have limited the applications to flows of low Reynolds numbers..

scholarly journals Evaluation of the Turbulence Model Influence on the Numerical Simulations of Unsteady Cavitation

2003 ◽  
Vol 125 (1) ◽  
pp. 38-45 ◽  
Author(s):  
O. Coutier-Delgosha ◽  
R. Fortes-Patella ◽  
J. L. Reboud
Keyword(s):  
Numerical Simulations ◽  
Stokes Equations ◽  
Simple Algorithm ◽  
Numerical Code ◽  
Navier Stokes ◽  
Finite Volume Scheme ◽  
Cavitating Flows ◽  
Two Phase ◽  
Navier Stokes Equations ◽  
Compressibility Effects

Unsteady cavitation in a Venturi-type section was simulated by two-dimensional computations of viscous, compressible, and turbulent cavitating flows. The numerical model used an implicit finite volume scheme (based on the SIMPLE algorithm) to solve Reynolds-averaged Navier-Stokes equations, associated with a barotropic vapor/liquid state law that strongly links the density variations to the pressure evolution. To simulate turbulence effects on cavitating flows, four different models were implemented (standard k-ε RNG; modified k-ε RNG; k-ω with and without compressibility effects), and numerical results obtained were compared to experimental ones. The standard models k-ε RNG and k-ω without compressibility effects lead to a poor description of the self-oscillation behavior of the cavitating flow. To improve numerical simulations by taking into account the influence of the compressibility of the two-phase medium on turbulence, two other models were implemented in the numerical code: a modified k-ε model and the k-ω model including compressibility effects. Results obtained concerning void ratio, velocity fields, and cavitation unsteady behavior were found in good agreement with experimental ones. The role of the compressibility effects on turbulent two-phase flow modeling was analyzed, and it seemed to be of primary importance in numerical simulations.

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