SAM
https://sam.ensam.eu:443
The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sun, 31 May 2020 08:36:38 GMT2020-05-31T08:36:38ZComparison of various hemodynamic models for applications to cfd in stented arteries
http://hdl.handle.net/10985/15875
Comparison of various hemodynamic models for applications to cfd in stented arteries
CHABI, Fatiha; CHAMPMARTIN, Stéphane; SARRAF, Christophe; NOGUERA, Ricardo; MAUREL, Blandine
A design study of propeller hydrokinetic turbines is explored in the present paper, where the optimized blade geometry is determined by the classical Glauert theory applicable to the design of axial flow turbines (hydrokinetic and wind turbines). The aim of the present study is to evaluate the optimized geometry for propeller hydrokinetic turbines, observing the effect of the number of blades in the runner design. The performance of runners with different number of blades is evaluated in a specific low-rotational-speed operating conditions, using blade element momentum theory (BEMT) simulations, confirmed by measurements in wind tunnel experiments for small-scale turbine models. The optimum design values of the power coefficient, in the operating tip speed ratio, for two-, three- and four-blade runners are pointed out, defining the best configuration for a propeller 10 kW hydrokinetic machine.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/158752014-01-01T00:00:00ZCHABI, FatihaCHAMPMARTIN, StéphaneSARRAF, ChristopheNOGUERA, RicardoMAUREL, BlandineA design study of propeller hydrokinetic turbines is explored in the present paper, where the optimized blade geometry is determined by the classical Glauert theory applicable to the design of axial flow turbines (hydrokinetic and wind turbines). The aim of the present study is to evaluate the optimized geometry for propeller hydrokinetic turbines, observing the effect of the number of blades in the runner design. The performance of runners with different number of blades is evaluated in a specific low-rotational-speed operating conditions, using blade element momentum theory (BEMT) simulations, confirmed by measurements in wind tunnel experiments for small-scale turbine models. The optimum design values of the power coefficient, in the operating tip speed ratio, for two-, three- and four-blade runners are pointed out, defining the best configuration for a propeller 10 kW hydrokinetic machine.Critical evaluation of three hemodynamic models for the numerical simulation of intra-stent flows
http://hdl.handle.net/10985/9961
Critical evaluation of three hemodynamic models for the numerical simulation of intra-stent flows
CHABI, Fatiha; CHAMPMARTIN, Stéphane; SARRAF, Christophe; NOGUERA, Ricardo
We evaluate here three hemodynamic models used for the numerical simulation of bare and stented artery flows. We focus on two flow features responsible for intra-stent restenosis: the wall shear stress and the re-circulation lengths around a stent. The studied models are the Poiseuille profile, the simplified pulsatile profile and the complete pulsatile profile based on the analysis of Womersley. The flow rate of blood in a human left coronary artery is considered to compute the velocity profiles. “Ansys Fluent 14.5” is used to solve the Navier–Stokes and continuity equations. As expected our results show that the Poiseuille profile is questionable to simulate the complex flow dynamics involved in intra-stent restenosis. Both pulsatile models give similar results close to the strut but diverge far from it. However, the computational time for the complete pulsatile model is five times that of the simplified pulsatile model. Considering the additional “cost” for the complete model, we recommend using the simplified pulsatile model for future intra-stent flow simulations.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/99612015-01-01T00:00:00ZCHABI, FatihaCHAMPMARTIN, StéphaneSARRAF, ChristopheNOGUERA, RicardoWe evaluate here three hemodynamic models used for the numerical simulation of bare and stented artery flows. We focus on two flow features responsible for intra-stent restenosis: the wall shear stress and the re-circulation lengths around a stent. The studied models are the Poiseuille profile, the simplified pulsatile profile and the complete pulsatile profile based on the analysis of Womersley. The flow rate of blood in a human left coronary artery is considered to compute the velocity profiles. “Ansys Fluent 14.5” is used to solve the Navier–Stokes and continuity equations. As expected our results show that the Poiseuille profile is questionable to simulate the complex flow dynamics involved in intra-stent restenosis. Both pulsatile models give similar results close to the strut but diverge far from it. However, the computational time for the complete pulsatile model is five times that of the simplified pulsatile model. Considering the additional “cost” for the complete model, we recommend using the simplified pulsatile model for future intra-stent flow simulations.Comparison of various hemodynamic models for applications to CFD in stent arteries
http://hdl.handle.net/10985/10255
Comparison of various hemodynamic models for applications to CFD in stent arteries
CHABI, Fatiha; CHAMPMARTIN, Stéphane; SARRAF, Christophe; NOGUERA, Ricardo; MAUREL, Blandine
This work assesses three hemodynamic models for the numerical modeling of intra-stent flows. These are the classical Poiseuille model (PM), the simplified pulsatile model (SPM) and the complete pulsatile model (CPM) based on the analysis of Womersley. They are applied to the physiological flow rate of a stented left coronary artery. The CFD package "Ansys Fluent 14.5" is used to compute the main features of the flows. The results show large differences between the steady and unsteady models notably for the wall shear stress and the re-circulation lengths, which are known to promote intra-stent restenosis. The PM is obviously not pertinent to calculate the flows involved in intra-stent restenosis. The CPM and SPM give close results but the latter model is by far less time-demanding and should be preferred.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/102552014-01-01T00:00:00ZCHABI, FatihaCHAMPMARTIN, StéphaneSARRAF, ChristopheNOGUERA, RicardoMAUREL, BlandineThis work assesses three hemodynamic models for the numerical modeling of intra-stent flows. These are the classical Poiseuille model (PM), the simplified pulsatile model (SPM) and the complete pulsatile model (CPM) based on the analysis of Womersley. They are applied to the physiological flow rate of a stented left coronary artery. The CFD package "Ansys Fluent 14.5" is used to compute the main features of the flows. The results show large differences between the steady and unsteady models notably for the wall shear stress and the re-circulation lengths, which are known to promote intra-stent restenosis. The PM is obviously not pertinent to calculate the flows involved in intra-stent restenosis. The CPM and SPM give close results but the latter model is by far less time-demanding and should be preferred.