Natural Steady Convection in a Space Annulus Between Two Elliptic Confocal Ducts: Influence of the Slope Angle

2005 ◽  
Vol 73 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Mahfoud Djezzar ◽  
Michel Daguenet
Keyword(s):  
Slope Angle ◽  
Boussinesq Equations ◽  
Annular Space ◽  
Arbitrary Angle ◽  
Elliptic Coordinates ◽  
System A ◽  
Pressure Formulation ◽  
Velocity Pressure ◽  
Steady Convection ◽  
Calculation Code

The authors express the Boussinesq equations of the laminar thermal and natural convection, in the case of permanent and bidimensional flow, in an annular space between two confocal elliptic cylinders. The latter is oriented at an arbitrary angle α with respect to the gravity force, using the elliptic coordinates system. A new calculation code using the finite volumes with the primitive functions (velocity-pressure formulation) is proposed. The Prandtl number is fixed at 0.7 (case of the air) with varying the Rayleigh number. The effect of the system inclination is examined.

Development and Application of Neutron Damage Calculation Code for ADS System

2013 ◽  
Author(s):  
Jun Zou ◽  
Chong Chen ◽  
Qin Zeng ◽  
Qi Yang ◽  
Zhong Chen
Keyword(s):  
Hydrogen Production ◽  
Research Reactor ◽  
Structural Materials ◽  
Lead Alloy ◽  
System A ◽  
Neutron Damage ◽  
Reasonable Range ◽  
Atom Displacement ◽  
Calculation Code

A neutron damage calculation code named NDCC was developed for the shielding analysis of ADS. The code can calculate atom displacement, helium and hydrogen production of the nuclides and compositions constituting the structural materials in ADS system. A benchmark was performed in China Lead-Alloy Cooled Research Reactor (CLEAR-I) to test the availability and reliability of the NDCC code. The discrepancy between the NDCC calculation and the results calculated by other codes fell into a reasonable range.

scholarly journals Analysis and Approximation of a Vorticity–Velocity–Pressure Formulation for the Oseen Equations

2019 ◽  
Vol 80 (3) ◽  
pp. 1577-1606 ◽  
Author(s):  
V. Anaya ◽  
A. Bouharguane ◽  
D. Mora ◽  
C. Reales ◽  
R. Ruiz-Baier ◽  
...  
Keyword(s):  
Oseen Equations ◽  
Pressure Formulation ◽  
Velocity Pressure

scholarly journals Recent Results from Analysis of Flow Structures and Energy Modes Induced by Viscous Wave around a Surface-Piercing Cylinder

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Giancarlo Alfonsi ◽  
Agostino Lauria ◽  
Leonardo Primavera
Keyword(s):  
Water Waves ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Wave Flow ◽  
Ocean Engineering ◽  
Navier Stokes Equations ◽  
Pressure Formulation ◽  
The Subject ◽  
Run Up ◽  
Velocity Pressure

Due to its relevance in ocean engineering, the subject of the flow field generated by water waves around a vertical circular cylinder piercing the free surface has recently started to be considered by several research groups. In particular, we studied this problem starting from the velocity-potential framework, then the implementation of the numerical solution of the Euler equations in their velocity-pressure formulation, and finally the performance of the integration of the Navier-Stokes equations in primitive variables. We also developed and applied methods of extraction of the flow coherent structures and most energetic modes. In this work, we present some new results of our research directed, in particular, toward the clarification of the main nonintuitive character of the phenomenon of interaction between a wave and a surface-piercing cylinder, namely, the fact that the wave exerts its maximum force and exhibits its maximum run-up on the cylindrical obstacle at different instants. The understanding of this phenomenon becomes of crucial importance in the perspective of governing the entity of the wave run-up on the obstacle by means of wave-flow-control techniques.

scholarly journals Vorticity-velocity-pressure formulation for Stokes problem

2003 ◽  
Vol 73 (248) ◽  
pp. 1673-1698 ◽  
Author(s):  
M. Amara ◽  
E. Chacón Vera ◽  
D. Trujillo
Keyword(s):  
Stokes Problem ◽  
Pressure Formulation ◽  
Velocity Pressure

scholarly journals A TIME DOMAIN METHOD FOR MODELING VISCOACOUSTIC WAVE PROPAGATION

2006 ◽  
Vol 14 (02) ◽  
pp. 201-236 ◽  
Author(s):  
JEAN-PHILIPPE GROBY ◽  
CHRYSOULA TSOGKA
Keyword(s):  
Wave Propagation ◽  
Time Domain ◽  
Mixed Finite Element ◽  
Mixed Finite Element Method ◽  
Propagation Model ◽  
Domain Method ◽  
Pressure Formulation ◽  
Complicated Geometry ◽  
The Time Domain ◽  
Velocity Pressure

In many applications, and in particular in seismology, realistic propagation media disperse and attenuate waves. This dissipative behavior can be taken into account by using a viscoacoustic propagation model, which incorporates a complex and frequency-dependent viscoacoustic modulus in the constitutive relation. The main difficulty then lies in finding an efficient way to discretize the constitutive equation as it becomes a convolution integral in the time domain. To overcome this difficulty the usual approach consists in approximating the viscoacoustic modulus by a low-order rational function of frequency. We use here such an approximation and show how it can be incorporated in the velocity-pressure formulation for viscoacoustic waves. This formulation is coupled with the fictitious domain method which permits us to model efficiently diffraction by objects of complicated geometry and with the Perfectly Matched Layer Model which allows us to model wave propagation in unbounded domains. The space discretization of the problem is based on a mixed finite element method and for the discretization in time a 2nd order centered finite difference scheme is employed. Several numerical examples illustrate the efficiency of the method.

scholarly journals Enhanced algorithms for solving the spectral discretization of the vorticity–velocity–pressure formulation of the Navier–Stokes problem

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Mohamed Abdelwahed ◽  
Nejmeddine Chorfi ◽  
Henda Ouertani
Keyword(s):  
Stokes Problem ◽  
Navier Stokes ◽  
Uzawa Method ◽  
Pressure Formulation ◽  
Velocity Pressure ◽  
Spectral Discretization

AbstractThe objective of the article is to improve the algorithms for the resolution of the spectral discretization of the vorticity–velocity–pressure formulation of the Navier–Stokes problem in two and three domains. Two algorithms are proposed. The first one is based on the Uzawa method. In the second one we consider a modified global resolution. The two algorithms are implemented and their results are compared.

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