hp analysis of a hybrid DG method for Stokes flow

2012 ◽  
Vol 33 (2) ◽  
pp. 687-721 ◽  
Author(s):  
H. Egger ◽  
C. Waluga
Keyword(s):  
Stokes Flow ◽  
Dg Method

A lowest-order staggered DG method for the coupled Stokes–Darcy problem

2020 ◽  
Vol 40 (4) ◽  
pp. 2871-2897 ◽  
Author(s):  
Lina Zhao ◽  
Eun-Jae Park
Keyword(s):  
Stokes Flow ◽  
Mass Conservation ◽  
Trace Inequality ◽  
Normal Forces ◽  
Darcy Problem ◽  
Dg Method ◽  
Regularization Operator ◽  
Convergence Estimates ◽  
Staggered Discontinuous Galerkin Method ◽  
Locally Conservative

Abstract In this paper we propose a locally conservative, lowest-order staggered discontinuous Galerkin method for the coupled Stokes–Darcy problem on general quadrilateral and polygonal meshes. This model is composed of Stokes flow in the fluid region and Darcy flow in the porous media region, coupling together through mass conservation, balance of normal forces and the Beavers–Joseph–Saffman condition. Stability of the proposed method is proved. A new regularization operator is constructed to show the discrete trace inequality. Optimal convergence estimates for all the approximations covering low regularity are achieved. Numerical experiments are given to illustrate the performances of the proposed method. The numerical results indicate that the proposed method can be flexibly applied to rough grids such as the trapezoidal grid and $h$-perturbation grid.

The Staggered DG Method is the Limit of a Hybridizable DG Method. Part II: The Stokes Flow

2015 ◽  
Vol 66 (2) ◽  
pp. 870-887 ◽  
Author(s):  
Eric Chung ◽  
Bernardo Cockburn ◽  
Guosheng Fu
Keyword(s):  
Stokes Flow ◽  
Dg Method

Chaotic Advection by Two-Dimensional Stokes Flow in a Semicircle

2004 ◽  
Vol 31 (4) ◽  
pp. 344-357
Author(s):  
T. A. Dunaeva ◽  
A. A. Gourjii ◽  
V. V. Meleshko
Keyword(s):  
Stokes Flow ◽  
Chaotic Advection ◽  
Two Dimensional

Evolution of unstable system.

2015 ◽  
Vol 9 (3) ◽  
pp. 2487-2502 ◽  
Author(s):  
Igor V. Lebed
Keyword(s):  
Reynolds Number ◽  
Vortex Shedding ◽  
Stokes Flow ◽  
Stable Solution ◽  
The State ◽  
Unstable System ◽  
Unstable Flow ◽  
Unstable Solutions ◽  
Vortex Shedding Modes ◽  
Hydrodynamics Equations

Scenario of appearance and development of instability in problem of a flow around a solid sphere at rest is discussed. The scenario was created by solutions to the multimoment hydrodynamics equations, which were applied to investigate the unstable phenomena. These solutions allow interpreting Stokes flow, periodic pulsations of the recirculating zone in the wake behind the sphere, the phenomenon of vortex shedding observed experimentally. In accordance with the scenario, system loses its stability when entropy outflow through surface confining the system cannot be compensated by entropy produced within the system. The system does not find a new stable position after losing its stability, that is, the system remains further unstable. As Reynolds number grows, one unstable flow regime is replaced by another. The replacement is governed tendency of the system to discover fastest path to depart from the state of statistical equilibrium. This striving, however, does not lead the system to disintegration. Periodically, reverse solutions to the multimoment hydrodynamics equations change the nature of evolution and guide the unstable system in a highly unlikely direction. In case of unstable system, unlikely path meets the direction of approaching the state of statistical equilibrium. Such behavior of the system contradicts the scenario created by solutions to the classic hydrodynamics equations. Unstable solutions to the classic hydrodynamics equations are not fairly prolonged along time to interpret experiment. Stable solutions satisfactorily reproduce all observed stable medium states. As Reynolds number grows one stable solution is replaced by another. They are, however, incapable of reproducing any of unstable regimes recorded experimentally. In particular, stable solutions to the classic hydrodynamics equations cannot put anything in correspondence to any of observed vortex shedding modes. In accordance with our interpretation, the reason for this isthe classic hydrodynamics equations themselves.

Positive Role of Synthesis Method and Hard Template on the Catalytic Performance of SAPO-34 in Methanol to Olefin Reaction.

2020 ◽  
Vol 23 ◽  
Author(s):  
Sajjad Rimaz ◽  
Reza Katal
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
Hard Template ◽  
Structure Directing Agent ◽  
Positive Role ◽  
Methanol To Olefin ◽  
Dg Method ◽  
Synthesis Procedure

: In the present study, SAPO-34 particles were synthesized using hydrothermal (HT) and dry gel (DG) conversion methods in the presence of diethyl amine (DEA) as an organic structure directing agent (SDA). Carbon nanotubes (CNT) were used as hard template in the synthesis procedure to introduce transport pores into the structures of the synthesized samples. The synthesized samples were characterized with different methods to reveal effects of synthesis method and using hard template on their structure and catalytic performance in methanol to olefin reaction (MTO). DG conversion method results in smaller particle size in comparison with hydrothermal method, resulting in enhancing catalytic performance. On the other side, using CNT in the synthesis procedure with DG method results in more reduction in particle size and formation of hierarchical structure which drastically improves catalytic performance.

Interactions Between Aggregated Particles in Stokes Flow

2008 ◽  
Author(s):  
J. Anushi Weliwita ◽  
Helen J. Wilson ◽  
Robert H. Davis ◽  
Albert Co ◽  
Gary L. Leal ◽  
...  
Keyword(s):  
Stokes Flow

Melt Modification and Microstructure Homogeneity of Solidified TiC-TiB2 Composites Prepared by Combustion Synthesis in Ultrahigh Gravity Field

2013 ◽  
Vol 833 ◽  
pp. 125-129
Author(s):  
Hao Zhang ◽  
Zhong Min Zhao ◽  
Long Zhang ◽  
Shuan Jie Wang
Keyword(s):  
Gravity Field ◽  
Combustion Synthesis ◽  
Stokes Flow ◽  
High Energy ◽  
Adiabatic Temperature ◽  
Full Density ◽  
Reactive System ◽  
Refined Microstructure ◽  
Ultrafine Grained ◽  
Ultrafine Grained Microstructure

By introducing (CrO3+Al) high-energy thermit into (Ti+B4C) system and designing adiabatic temperature of reactive system as 3000°C,3200°C, 3400°C, 3600°C and 3800°C respectively, a series of solidified TiC-TiB2were prepared by combustion synthesis in ultrahigh gravity field with the acceleration 2000 g. XRD, FESEM and EDS results showed that the solidified TiCTiB2were composed of a number of TiB2primary platelets, irregular TiC secondary grains, and a few of isolated Al2O3inclusions and Cr-based alloy. Because of the enhanced Stokes flow in mixed melt with the increased adiabatic temperature, Al2O3droplets were promoted to float up and separate from TiC-TiB2-Me liquid while constitutional distribution became more and more uniform in TiC-TiB2-Me liquid, resulting in not only the sharply-reduced Al2O3inclusions in the solidified ceramic but also the refined microstructure and the improved homogeneity in the ceramic, and ultrafine-grained microstructure with a average thickness of TiB2platelets smaller than 1μm began to appear in near-full-density ceramic as the adiabatic temperature exceeded 3600°C, so the densification, fracture toughness and flexural strength of the ceramic were enhanced with the increased adiabatic temperature of the reactive system.

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