arXiv subjects

Hashnayne Ahmed

Publications and source records attributed to Hashnayne Ahmed.

4 recordsLinked to original sources

arXiv2025

Hemodynamic Simulation in the Aortic Arch Under Anemic Diabetic and Healthy Blood Flow Conditions Using Computational Fluid Dynamics

This study investigates the hemodynamic behavior of blood flow in the aortic arch across anemic, diabetic, and healthy conditions using computational fluid dynamics (CFD) simulations with a non-Newtonian Carreau viscosity model. Velocity fields, pressure distributions, and wall shear stress (WSS) patterns were analyzed to assess the impact of blood rheology and vessel geometry. Anemic blood, with low viscosity and hematocrit, produced smooth, low-resistance flow with reduced WSS and pressure gradients, potentially impairing perfusion. Diabetic blood exhibited elevated viscosity, leading to increased flow resistance, higher WSS, and localized separation at arterial branches -- conditions associated with vascular stress and remodeling. Healthy cases showed balanced hemodynamic behavior with localized flow acceleration but maintained physiological ranges. These findings highlight the mechanistic links between rheological properties and cardiovascular stress, supporting the role of CFD in non-invasive vascular risk assessment and motivating future integration of patient-specific data and structural modeling for enhanced clinical relevance.

physics.flu-dyn↗

arXiv2024

Mixed Convection and Entropy Generation Analysis of Carbon Nanotube-Water Nanofluid in a Square Cavity with Cylinders and Flow Deflectors

This study explores the mixed convection of carbon nanotube (CNT)-water nanofluid within a square cavity containing heated cylinders under the influence of a magnetic field, focusing on three geometric configurations: a single heated cylinder, two heated cylinders, and two heated cylinders with a flow deflector. The impact of various parameters, including Reynolds number ($Re$), Richardson number ($Ri$), Hartmann number ($Ha$), wavy wall peaks ($n$), nanoparticle volume fraction ($\phi$), Hartmann angle ($\gamma$), rotational speed ($\omega$), and inclination angle ($\alpha$), on thermal and fluid dynamic behaviors is analyzed. MWCNT nanofluids exhibit up to a 19.1% increase in $Nu_{\text{ave}}$ compared to SWCNT nanofluids, confirming their superior heat transfer performance. Adding a second heated cylinder increases $Nu_{\text{ave}}$ by approximately 71.7% compared to a single-cylinder configuration, while the inclusion of a flow deflector modifies vortex structures, further enhancing convective transport. Increasing wavy wall peaks ($n$) enhances heat transfer by intensifying vortex formation and disrupting thermal boundary layers, leading to a more uniform temperature distribution. SWCNT nanofluids exhibit Bejan numbers up to 58.7% higher than MWCNT nanofluids, indicating greater thermal irreversibility. These findings provide valuable insights for optimizing thermal management systems in engineering applications, highlighting the importance of selecting appropriate nanofluids, geometric configurations, and magnetic field parameters to achieve optimal thermal performance and fluid stability.

physics.flu-dyn↗

arXiv2024

Mixed Convection Heat Transfer and Flow of Al2O3-Water Nanofluid in a Square Enclosure with Heated Obstacles and Varied Boundary Conditions

This paper studies the effects of mixed convection fluid motion and heat transmission of Al2O3-Water nanofluid in a square enclosure including two heated obstacles, with temperature and nanoparticle concentration being determined by the thermal conductivity and effective viscosity. The parametric observations of Richardson number, Reynolds number, cylinder rotating speed, and cavity inclination angles are investigated in the range of 0.1 \leq Ri \leq 10, 1 \leq Re \leq 125, 1 \leq \omega \leq 25, and 0^\degree \leq \gamma \leq 60^\degree respectively on the thermal environment and flow arrangement inside the cavitation field. Adding nanoparticles to the base fluid enhances the heat transfer rate for both obstacles and all ranges of the parameters. The influence of wavy walls, changes in the nanofluid, and distinct positional effects also impact the flow characteristics and heat transfer process.

physics.flu-dyn↗

arXiv2024

Hemodynamical Behavior Analysis of Anemic, Diabetic, and Healthy Blood Flow in the Carotid Artery

The influence of blood rheology on hemodynamic parameters is investigated using Computational Fluid Dynamics on blood flow through the human carotid artery. We performed three-dimensional modeling and simulation to study blood flow through the carotid artery, which is divided into internal and exterior parts with a decreased radius. The blood flow was classified as basic pulsatile to simulate the human heart's rhythmic pulses. For hemodynamic modeling viscosity of the fluid, the Carreau model was utilized with four distinct blood instances: Anemic, diabetic, and two healthy blood types. The boundary conditions with Carreau viscosity were applied using the Ansys Fluent simulator, and the governing equations were solved using the finite volume technique. Different time steps were tested for their impact on wall deformation, strain rate, blood velocity, pressure, wall shear, and skin friction coefficient. The hemodynamical parameters were calculated using many cross-sectional planes along the artery. Finally, the impact of the four types of blood cases listed above was investigated, and we discovered that each blood case has a substantial impact on blood velocity, pressure, wall shear, and strain rate along the artery.

physics.flu-dyn↗