Computation of turbulent flow inside an enclosure with central partition

Arun, M.; Tulapurkara, E. G.

doi:10.1504/pcfd.2005.007681

Cited by 10 publications

(5 citation statements)

References 9 publications

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“…Neither laminar flow modeling nor Reynolds Averaged Navier-Stokes (RANS) based turbulence models that are developed for fully turbulent flows are suitable for this kind of flows (36)(37)(38). The turbulence model utilized here is the transitional shear stress transport (SST) k-ω model designed to capture the transition, if any, to turbulent state (19,21,26).…”

Section: Transitional Shear Stress Transport (Sst) K-ω Turbulence Modelmentioning

confidence: 99%

Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries

Mahalingam¹,

Gawandalkar²,

Kini³

et al. 2016

Cardiovasc. Diagn. Ther.

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Background: Local hemodynamics plays an important role in atherogenesis and the progression of coronary atherosclerosis disease (CAD). The primary biological effect due to blood turbulence is the change in wall shear stress (WSS) on the endothelial cell membrane, while the local oscillatory nature of the blood flow affects the physiological changes in the coronary artery. In coronary arteries, the blood flow Reynolds number ranges from few tens to several hundreds and hence it is generally assumed to be laminar while calculating the WSS calculations. However, the pulsatile blood flow through coronary arteries under stenotic condition could result in transition from laminar to turbulent flow condition.Methods: In the present work, the onset of turbulent transition during pulsatile flow through coronary arteries for varying degree of stenosis (i.e., 0%, 30%, 50% and 70%) is quantitatively analyzed by calculating the turbulent parameters distal to the stenosis. Also, the effect of turbulence transition on hemodynamic parameters such as WSS and oscillatory shear index (OSI) for varying degree of stenosis is quantified. The validated transitional shear stress transport (SST) k-ω model used in the present investigation is the best suited Reynolds averaged Navier-Stokes turbulence model to capture the turbulent transition. The arterial wall is assumed to be rigid and the dynamic curvature effect due to myocardial contraction on the blood flow has been neglected.Results: Our observations shows that for stenosis 50% and above, the WSS avg , WSS max and OSI calculated using turbulence model deviates from laminar by more than 10% and the flow disturbances seems to significantly increase only after 70% stenosis. Our model shows reliability and completely validated.Conclusions: Blood flow through stenosed coronary arteries seems to be turbulent in nature for area stenosis above 70% and the transition to turbulent flow begins from 50% stenosis.

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Section: Transitional Shear Stress Transport (Sst) K-ω Turbulence Modelmentioning

confidence: 99%

Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries

Mahalingam¹,

Gawandalkar²,

Kini³

et al. 2016

Cardiovasc. Diagn. Ther.

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“…where U is the velocity (m/s), l m is the dynamic viscosity (Pa-s), p is the static pressure (Pa), q is the fluid density (kg/m 3 ), and _ # is shear rate (1/s). The shear stress transport (SST) k-x model is used as the turbulence model [29,30]. The sinusoidal motion of piston in the cylinder is achieved by writing sine function with the help of CEL and the moving mesh option provides privilege for the motion of the piston.…”

Section: Computational Fluid Dynamic (Cfd) Analysis Of Mr Dampermentioning

confidence: 99%

An approach for characterizing twin-tube shear-mode magnetorheological damper through coupled FE and CFD analysis

Gurubasavaraju

Kumar

Mahalingam

2018

J Braz. Soc. Mech. Sci. Eng.

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The most promising technology in the field of semi-active suspension systems is the use of magnetorheological property of MR fluid, whose material behavior can be controlled through external magnetic field. Devices developed based on this principle are adaptive and controllable as desired for a specific application. It is important to understand the damping characteristics of these devices before employing them, using experimental or computational approaches. In the present work, both experimental and computational methods have been adopted for characterizing a twin-tube MR damper with an intention to develop a computational approach as an alternative to experimental test in the preliminary design stage. Initially, experimental characterization of MR damper was carried out at 1.5 and 2 Hz frequencies for damper stroke length of ± 5 mm under different DC currents ranging from 0.1 to 0.4 A. Later, coupled finite-element and computational fluid dynamic analysis has been carried out to estimate the damping force under same conditions as used in the experiment. The results of computation are in good agreement with experimental ones. Furthermore, using this computational approach, the damping force at different frequencies of 1.5, 2, 3, and 4 Hz has been estimated and its time histories are also plotted. The influence of fluid flow gap on the damping force has been determined and results revealed that damping force behaves inversely with fluid flow gap.

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“…The shear stress transport (SST) k-ω model is used as the turbulence model. 43,44 The sinusoidal motion of piston in the cylinder is achieved by writing sine function with the help of command expression language (CEL) and the moving mesh option provides provision for the motion of the piston. Newtonian and magnetized non-Newtonian region (shear flow gap) are specified by writing CFX command language (CCL) 53 when the piston is under motion in the same computational domain.…”

Section: Coupled Fea and Cfd Analysis Of Shear Mode Mr Dampermentioning

confidence: 99%

Performance analysis of a semi-active suspension system using coupled CFD-FEA based non-parametric modeling of low capacity shear mode monotube MR damper

Mata

Kumar

Mahalingam

2018

Proceedings of the Institution of Mechanical Engineers, Part D:

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In this work, an approach for formulation of a non-parametric-based polynomial representative model of magnetorheological damper through coupled computational fluid dynamics and finite element analysis is presented. Using this, the performance of a quarter car suspension subjected to random road excitation is estimated. Initially, prepared MR fluid is characterized to obtain a relationship between the field-dependent shear stress and magnetic flux density. The amount of magnetic flux induced in the shear gap of magnetorheological damper is computed using finite element analysis. The computed magnetic field is used in the computational fluid dynamic analysis to calculate the maximum force induced under specified frequency, displacement and applied current using ANSYS CFX software. Experiments have been conducted to verify the credibility of the results obtained from computational analysis, and a comparative study has been made. From the comparison, it was found that a good agreement exists between experimental and computed results. Furthermore, the influence of fluid flow gap length and frequency on the induced force of the damper is investigated using the computational methods (finite element analysis and computational fluid dynamic) for various values. This proposed approach would serve in the preliminary design for estimation of magnetorheological damper dynamic performance in semi-active suspensions computationally prior to experimental analysis.

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Computation of turbulent flow inside an enclosure with central partition

Cited by 10 publications

References 9 publications

Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries

Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries

An approach for characterizing twin-tube shear-mode magnetorheological damper through coupled FE and CFD analysis

Performance analysis of a semi-active suspension system using coupled CFD-FEA based non-parametric modeling of low capacity shear mode monotube MR damper

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