arXiv subjects

Osman Aycan

Publications and source records attributed to Osman Aycan.

3 recordsLinked to original sources

arXiv2026

Hemodynamic Performance and Blood Damage of the Intra-Aortic Pumps: A CFD-Based Investigation

Three intra-aortic blood pumps were evaluated and compared using CFD simulations. The aim of this study is to evaluate the hemodynamic performance and calculate the hemolytic potential of the pumps. The flow fields generated by the pumps were simulated using CFD with a wall-modeled large eddy simulation (WMLES) approach. The simulations produced pressure-flow curves, hydraulic efficiency, shear stress distributions, and hemolysis predictions. A grid study was conducted using the Grid Convergence Index (GCI) method, and a new dimensionless parameter, the Hemolytic Number (HN), was introduced as a standardized metric to compare hemolysis and universal pump performance. The impeller-driven pump had the highest-pressure head (~800 Pa at 4 L/min) and the best hydraulic efficiency (~6% at 14 L/min), outperforming both the single (maximum 2.7%) and triplet (maximum 2.2%) pumps. The NIH values were also lowest for the impeller pump (NIH = 0.0035 g/100L), indicating high hemocompatibility. Both the single and triplet pumps showed regions of recirculation, particularly at lower flow rates. A smaller HN indicates better hemocompatibility; for the impeller-driven pump, HN remains below 1 across the investigated flow rates. Overall, the impeller-driven pump outperformed the other designs in terms of both hemodynamic and hemolytic measurements. The findings provide valuable insights for the future development of intra-aortic pumps and the personalized selection of devices for individual patients.

physics.med-ph↗

arXiv2025

Numerical investigation of the flow induced by a transcatheter intra-aortic entrainment pump

This study evaluates the fluid dynamics inside and outside transcatheter blood pump positioned in the aorta. We focus on the pump's impact on blood component damage and arterial wall stress. CFD simulations were performed for rotational speeds ranging from 6000 to 15000 rpm, with a blood flow rate of 1.6 L/min. Results show that significant blood damage may occur at speeds as low as 12000 rpm, and the pump's outflow jet induces elevated wall shear stress, potentially leading to arterial aneurysms. These findings suggest the need for further design improvements to reduce risks when used in prolonged or transplant-related applications.

physics.flu-dyn↗

arXiv2023

Evaluating Uncertainties in CFD Simulations of Patient-Specific Aorta Models using Grid Convergence Index Method

Cardiovascular diseases are among the most important causes of global mortality. Computational Fluid Dynamics (CFD) is a powerful research tool that analyzes the hemodynamics of artery and blood flow patterns. In this study, CFD simulations are performed to assess the patient-specific healthy aorta, fusiform, and saccular aneurysm with various mesh types, including tetrahedral, polyhedral, and poly-hexacore. The aim of this study is to explore how different mesh types and grid densities impact the hemodynamic properties of physiological flows, with the goal of identifying the most cost-effective meshing approach. A mesh independence study is carried out to ensure the precision of the results, considering the wall shear stress distribution. For this, five different mesh resolutions are generated for each geometry. The uncertainties of the simulations associated with the discretization techniques and solutions are evaluated using the Grid Convergence Index (GCI) method. The findings showed that increasing the mesh density provides smaller uncertainty. GCI values for the wall shear stress are in the range of convergence, indicating that the results are reliable and accurate. Mesh type selection affects the accuracy and computational cost of our simulations. The polyhedral and poly-hexacore meshes lead to a good compromise between precision and computational cost, while the tetrahedral mesh style gives the most precise results with fluctuation. This work provides a systematic approach based on the Grid Convergence Index method in order to select the most appropriate mesh type for evaluating uncertainties in CFD simulations of patient-specific healthy aortas and aortas with abdominal aneurysms. According to the findings and GCI analysis, the polyhedral mesh type was chosen for all patient-specific aorta models. The study clearly demonstrated its superiority over other mesh types, ...

physics.flu-dyn↗