Inlet boundary conditions for the simulation of fluid dynamics in gas–solid fluidized beds

2006 ◽  
Vol 61 (16) ◽  
pp. 5183-5195 ◽  
Author(s):  
Srdjan Sasic ◽  
Filip Johnsson ◽  
Bo Leckner
Keyword(s):  
Fluid Dynamics ◽  
Boundary Conditions ◽  
Fluidized Beds

scholarly journals A Simple Transient Poiseuille-Based Approach to Mimic the Womersley Function and to Model Pulsatile Blood Flow

Dynamics ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 9-17
Author(s):  
Andrea Natale Impiombato ◽  
Giorgio La Civita ◽  
Francesco Orlandi ◽  
Flavia Schwarz Franceschini Zinani ◽  
Luiz Alberto Oliveira Rocha ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Boundary Conditions ◽  
Quadratic Function ◽  
Pulsatile Blood Flow ◽  
Flow Through ◽  
Simplified Analysis ◽  
Function Models ◽  
Flow Reversals

As it is known, the Womersley function models velocity as a function of radius and time. It has been widely used to simulate the pulsatile blood flow through circular ducts. In this context, the present study is focused on the introduction of a simple function as an approximation of the Womersley function in order to evaluate its accuracy. This approximation consists of a simple quadratic function, suitable to be implemented in most commercial and non-commercial computational fluid dynamics codes, without the aid of external mathematical libraries. The Womersley function and the new function have been implemented here as boundary conditions in OpenFOAM ESI software (v.1906). The discrepancy between the obtained results proved to be within 0.7%, which fully validates the calculation approach implemented here. This approach is valid when a simplified analysis of the system is pointed out, in which flow reversals are not contemplated.

A New Formulation for Computational Fluid Dynamics

1979 ◽  
Vol 101 (4) ◽  
pp. 453-460
Author(s):  
D. B. Reed ◽  
W. L. Oberkampf
Keyword(s):  
Fluid Dynamics ◽  
Boundary Conditions ◽  
Transport Equation ◽  
Mesh Size ◽  
Channel Length ◽  
Test Case ◽  
Parallel Plates ◽  
Flow Problems ◽  
Vector Quantity ◽  
New Formulation

A new vector quantity in fluid dynamics is defined and a vector transport equation for the quantity is derived. The new vector quantity is defined as the curl of the vorticity and is referred to as the angular vorticity. The transport equation for the new quantity is derived by taking the curl of the vorticity transport equation. The new transport equation combined with Poisson type velocity equations comprises the new angular vorticity-velocity formulation. The major advantage of the new formulaton is that computational boundary conditions for through-flow problems may be significantly relaxed. Boundary conditions for the newly defined variable are derived. A simple test case of laminar incompressible planar flow between parallel plates was executed to determine if the new formulation would produce results comparable to previous solutions. Numerical experiments were conducted using channel length, mesh size, and Reynolds number as parameters. The results are compared to values obtained by other investigators. The results show that the angular vorticity formulation is a feasible method for solution of fluid flow problems where fully developed flow is not attained.

On the Use of Atmospheric Boundary Conditions for Axial-Flow Compressor Stall Simulations

2004 ◽  
Vol 127 (2) ◽  
pp. 349-351 ◽  
Author(s):  
M. Vahdati ◽  
A. I. Sayma ◽  
C. Freeman ◽  
M. Imregun
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Boundary Conditions ◽  
Hysteresis Loop ◽  
Axial Flow ◽  
Computational Domain ◽  
Computational Fluid Dynamics Cfd ◽  
Fan Blade ◽  
Flow Compressor ◽  
Speed Characteristic

This paper describes a novel way of prescribing computational fluid dynamics (CFD) boundary conditions for axial-flow compressors. The approach is based on extending the standard single passage computational domain by adding an intake upstream and a variable nozzle downstream. Such a route allows us to consider any point on a given speed characteristic by simply modifying the nozzle area, the actual boundary conditions being set to atmospheric ones in all cases. Using a fan blade, it is shown that the method not only allows going past the stall point but also captures the typical hysteresis loop behavior of compressors.

Fluid dynamics of gas-liquid-solid fluidized beds

1986 ◽  
Vol 25 (4) ◽  
pp. 849-854 ◽  
Author(s):  
Enrique Costa ◽  
Antonio De Lucas ◽  
Pedro Garcia
Keyword(s):  
Fluid Dynamics ◽  
Fluidized Beds

scholarly journals Detailed computational and experimental fluid dynamics of fluidized beds

2006 ◽  
Vol 30 (11) ◽  
pp. 1459-1471 ◽  
Author(s):  
N.G. Deen ◽  
M. Van Sint Annaland ◽  
J.A.M. Kuipers
Keyword(s):  
Fluid Dynamics ◽  
Fluidized Beds ◽  
Experimental Fluid Dynamics ◽  
Experimental Fluid

Uncertainty in Computational Fluid Dynamics

1996 ◽  
Vol 210 (1) ◽  
pp. 91-94 ◽  
Author(s):  
E H Fisher ◽  
N Rhodes
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Quality Assurance ◽  
Boundary Conditions ◽  
Error Estimation ◽  
Validation Studies ◽  
Postgraduate Training ◽  
Sources Of Uncertainty ◽  
Expert Meeting ◽  
Computational Fluid Dynamics Cfd

The Annual EPSRC/IMechE Expert Meeting brought together some 44 experts to consider sources of uncertainty in computational fluid dynamics (CFD). Presentations and discussions covered modelling, numerical solution techniques, boundary conditions, evaluation protocols and QA (quality assurance) procedures. The principal conclusions to emerge were: (a) the need for additional collaborative validation studies; (b) the desirability of introducing appropriate QA procedures, possibly based on the CFD Community Club initiative; (c) the need for additional postgraduate training, possibly based on the IGDS principle; (d) the value of continuing work in modelling and error estimation techniques for numerical schemes.

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