An algebraic boundary orthogonalization procedure for structured grids

Lehtimäki, Reijo

doi:10.1002/(sici)1097-0363(20000315)32:5<605::aid-fld986>3.0.co;2-5

Cited by 3 publications

(1 citation statement)

References 7 publications

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“…The verification is performed by some controlling parameters such as skewness value 37 and maximum grid aspect ratio (MAR). 38 MAR. Bounding all the maximum aspect ratios is essential for preventing grid lines from collapsing onto each other and high-quality numerical approximations.…”

Section: Grid Qualitymentioning

confidence: 99%

Numerical investigation of the hydrodynamic parameters of blood flow through stenotic descending aorta

Zanous

Shafaghat

Esmaili

2015

Proc Inst Mech Eng H

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In this study, the blood flow passing through a three-dimensional geometrically realistic stenosis is investigated both experimentally and numerically. Although the blood flow in stenotic arteries has been extensively studied in the past few decades, not much work has been focused on irregularity of stenosis. Thus, a model of an irregular stenotic descending aorta is used in this work. Due to the irregularity of stenosis model, the governing differential equations for continuity and momentum are solved numerically using finite-volume/finite-difference techniques in the generalized body-fitted coordinates. In order to verify the numerical results, the experimental measured pressure drops are compared with the numerical result. In addition, an improved method for nearly orthogonal grid generation is presented in numerical study. The grid generating system is based on the solution of a set of partial differential equations with finite difference discretization. Numerical calculations are performed to examine the effect of 55% (ratio between cross-sectional area at upstream and stenosis) irregular stenosis on the hemodynamic characteristics such as flow separation zone, wall shear stress and pressure drop. The maximum calculated wall shear stress is related to the maximum velocity gradient due to minimum cross-sectional area at the neck of stenosis. In addition, the pressure is shown as an important characteristic that is effecting on the resistance against the flow in the artery. Based on our results, the 55% irregular constriction is considered critical unlike the studies that have believed the reduction, which is greater than 75% become significant.

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Section: Grid Qualitymentioning

confidence: 99%

Numerical investigation of the hydrodynamic parameters of blood flow through stenotic descending aorta

Zanous

Shafaghat

Esmaili

2015

Proc Inst Mech Eng H

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Three Dimensional Numerical Analysis of Screw Compressor Performance

Kovačević

Stošić

Smith

2003

JCM

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Modern manufacturing methods enable screw compressors to be constructed to such close tolerances that full 3-D numerical calculation of the heat and fluid flow through them is required to obtain the maximum possible improvements in their design. An independent stand-alone CAD-CFD interface program has therefore been developed by the authors in order to generate a numerical grid for this purpose. Modifications implemented to the CFD procedure improved solutions in complex domains with strong pressure gradients. The interface employs a procedure to produce rotor profiles and an analytical transfinite interpolation method to obtain a fully structured 3-D numerical mesh, which is directly transferable to a CFD code. Some features, which include an adaptive meshing procedure, mesh orthogonalization and smoothing, are employed to generate a numerical mesh which can take advantage of the techniques used in recent finite volume numerical method solvers. These were required to overcome problems associated with i) rotor domains which stretch and slide relative to each other and along the housing ii) robust calculations in domains with significantly different geometry ranges. iii) a grid moving technique with a constant number of vertices. Some changes had to be made within the solver functions to increase the speed of calculation. These include a means to maintain constant pressures at the inlet and outlet ports and consideration of two-phase flow resulting from oil injection in the working chamber. The pre-processor code and calculating method have been tested on a commercial CFD solver to obtain flow simulations and integral parameter calculations. The results of calculations on an oil injected screw compressor are presented in this paper and compared with experimental results.

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