Amin Deyranlou | Ferdowsi University of Mashhad (original) (raw)

Papers by Amin Deyranlou

Emerging Trends in Mechatronics, 2023

Emerging Trends in Mechatronics

Lumped (zero-dimensional) technique is a robust and widely used approach to mathematically model ... more Lumped (zero-dimensional) technique is a robust and widely used approach to mathematically model and explore bulk behaviour of different physical phenomena in a lower expense. In modelling of cardio/cerebrovascular fluid dynamics, this technique facilitates the assessment of relevant metrics such as flow, pressure, and temperature at different locations over a large network/domain. Furthermore, they can be employed as boundary conditions in multiscale modelling of physiological flows. In this methodology paper, a lumped model for the cardiovascular flow simulation along with a two-node thermoregulation model are employed. The lumped models are built upon previous studies and are amended appropriately to focus on cardiac function. The output of the coupled model can either be used for assessing the cardiac function in different physiological conditions or it can provide the input data for other investigations. Noteworthy to mention that, the present model has been specifically develo...

دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا يارب : Please cite this article using: A. Deyranlo... more دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا يارب : Please cite this article using: A. Deyranlou, H. Niazmand, M.R. Sadeghi, Investigation of effective parameters on accumulation of low-density lipoproteins based on the multilayer wall of the carotid artery , Modares Mechanical Engineering, Vol. 14, No. 4, pp. 27-36, 2014 (In Persian) نیئتورپوپیل تشابنا رب رثؤم لماوع یسررب لدم يانبم رب نییاپ هتیسناد اب اه هیلا دنچ دیتوراک نایرش هراوید

دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا يارب : Please cite this article using: A. Deyranlo... more دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا يارب : Please cite this article using: A. Deyranlou, H. Niazmand, Y. Mesri, Blood pulsatile effect on LDL mass transport in a multilayered carotid artery with atherosclerotic plaques, Modares Mechanical Engineering, Vol. 14, No. 7, pp. 17-26, 2014 (In Persian) گرخرس رد نییاپ هتیسناد اب نیئتورپوپیل تارذ مرج لاقتنا رب نوخ ینابرض نایرج ریثات كلاپ ياراد هیلادنچ هراوید اب دیتوراک کیتورلکسورتآ ياه

Frontiers in Bioengineering and Biotechnology, 2020

Congenital heart disease (CHD) is the most common birth defect globally and coarctation of the ao... more Congenital heart disease (CHD) is the most common birth defect globally and coarctation of the aorta (CoA) is one of the commoner CHD conditions, affecting around 1/1800 live births. CoA is considered a CHD of critical severity. Unfortunately, the prognosis for a child born in a low and lower-middle income country (LLMICs) with CoA is far worse than in a high-income country. Reduced diagnostic and interventional capacities of specialists in these regions lead to delayed diagnosis and treatment, which in turn lead to more cases presenting at an advanced stage. Computational fluid dynamics (CFD) is an important tool in this context since it can provide additional diagnostic data in the form of hemodynamic parameters. It also provides an in silico framework, both to test potential procedures and to assess the risk of further complications arising post-repair. Although this concept is already in practice in high income countries, the clinical infrastructure in LLMICs can be sparse, and access to advanced imaging modalities such as phase contrast magnetic resonance imaging (PC-MRI) is limited, if not impossible. In this study, a pipeline was developed in conjunction with clinicians at the Red Cross War Memorial Children's Hospital, Cape Town and was applied to perform a patient-specific CFD study of CoA. The pipeline uses data acquired from CT angiography and Doppler transthoracic echocardiography (both much more clinically available than MRI in LLMICs), while segmentation is conducted via SimVascular and simulation is realized using OpenFOAM. The reduction in cost through use of open-source software and the use of broadly available imaging modalities

International Journal of Modern Physics C, 2020

Over the past few decades, different therapeutic methods for the treatment of intracranial aneury... more Over the past few decades, different therapeutic methods for the treatment of intracranial aneurysms have been developed. During recent years, novel standalone intrasaccular Woven EndoBridge (WEB) technique has paved the way for efficient therapy and reduced some deficiencies in prior procedures. Blood hemodynamics plays a crucial role in occurrence and perpetuating of aneurysm; therefore, understanding of relevant parameters can lead to a better treatment and evolution of design. Objectively, this paper has established the first mathematical framework to explore hemodynamic parameters for WEB-treated saccular aneurysms by employing Computational Fluid Dynamics (CFD). Two ideal models of artery — one is suffered by a bifurcation aneurysm at Basilar Artery (BA) and another Posterior Cerebral Artery (PCA) aneurysm — are selected. Simulations are performed for an untreated and three WEB-treated aneurysms by Dual Layer (DL), Single Layer (SL) and Single Layer Sphere (SLS) WEBs. Results ...

Annals of Biomedical Engineering, 2020

Atrial fibrillation (AF) is the most common type of arrhythmia, which undermines cardiac function... more Atrial fibrillation (AF) is the most common type of arrhythmia, which undermines cardiac function. Atrial fibrillation is a multi-facet malady and it may occur as a result of other diseases or it may trigger other problems. One of the main complications of AF is stroke due to the possibility of clot formation inside the atrium. However, the possibility of stroke occurrence due to the AF and the location from which an embolus dispatches are subject of debate. Another hypothesis about the embolus formation during AF is thrombus formation in aorta and carotid arteries, embolus detachment and its movement. To investigate the possibility of the latter postulation, the current work suggests a parametric study to quantify the sensitivity of aortic flow to four common AF traits including lack of atrial kick, atrial remodelling, left ventricle systolic dysfunction, and high frequency fibrillation. The simulation was carried out by coupling several in-house codes and ANSYS-CFX module. The res...

European Heart Journal, 2019

Background Tetralogy of Fallot (ToF) and coarctation of the aorta (CoA) each constitute approxima... more Background Tetralogy of Fallot (ToF) and coarctation of the aorta (CoA) each constitute approximately 7% of congenital heart disease (CHD) births worldwide. Compared to developed countries, developing countries have a disparate level of access to prompt diagnosis and treatment for these diseases. Computational fluid dynamics (CFD) approaches implemented on routinely available non-invasive imaging data may yield low-cost improvements to the management of these patients. Purpose The purpose of this research is to develop a patient-specific computational pipeline that allows the modelling of blood flow in diseased arteries of patients suffering from ToF and CoA. The project aims to prove the feasible use of broadly available imaging techniques - CT angiograms (CTA) and echocardiographs (echo) - for achieving this in low-to-middle income countries. The capability of the pipeline will be demonstrated through a qualitative study of the effects of different systemic to pulmonary shunt conf...

This paper presents a numerical study of the gas–powder flow in a typical Lapple cyclone with div... more This paper presents a numerical study of the gas–powder flow in a typical Lapple cyclone with division of gas and particle flow in a vortex finder. The Navier-Stokes equations along with the RNG k-ε turbulent model are solved numerically. The separation efficiency and the trajectory of particles are simulated and the effects of the particle size on the separation efficiency and the particle residence time are investigated. The effect of the particle density on the particle size in the range which results 100% cyclone separation efficiency and particle residensce time is investigated. Large particles generally have a higher concentration in the wall region and small particles have a higher concentration in the inner vortex region. Particles enter from different sides give different separation efficiency and trajectory. A particle with a size exceeding a critical diameter or a critical density would stagnate on the wall of the cyclone’s cone. This phenomenon is regarded as a main reason for the deposition on the inner conical surface in such cyclones used in cement industry.

مشاهدات زیادی نشان داده‌اند که بیماری تصلب شراین در عروق خمیده و محل چند شاخگی عروق که همودینامیک... more مشاهدات زیادی نشان داده‌اند که بیماری تصلب شراین در عروق خمیده و محل چند شاخگی عروق که همودینامیک پیچیده دارند، اتفاق می‌افتد. معمولاً تنش‌های برشی نوسانی بزرگ یا کوچکی در این نواحی در دیواره عروق ایجاد می¬شود در مطالعه¬ی حاضر جریان سه¬بعدی خون، همراه با پروفیل سرعت و فشار واقعی در شریان کاروتید داخلی با سه هندسه¬ی واقعی متفاوت و با استفاده از نرم‌افزار اپن فوم مورد مطالعه قرارگرفته است. سه مدلی که در آن‌ها تنش برشی دیواره حائز اهمیت است، مشخص گردیده و خطر گرفتی در این نواحی با توجه به ‌سرعت محوری و مقادیر تنش برشی دیواره مورد مطالعه قرارگرفته است. حل عددی توسط مقایسه با نتایج آزمایشگاهی درون خم 90 درجه اعتبار سنجی شده است. نظریه محل گرفتگی در سه هندسه¬ی مختلف کاروتید داخلی بررسی و مشخص ¬شده که شکل هندسی عروق تأثیر بسزایی در ایجاد گرفتگی¬ها دارند. احتمال شروع این بیماری در خم¬های بزرگ، بیشتر است؛ زیرا که در این نواحی تنش برشی دیواره کوچک‌تر و شاخص تنش نوسانی بزرگ می¬شود در نتیجه مطالعه¬ی هندسی امکان تشخیص مکان¬های مستعد گرفتگی را فراهم می¬آورد.

Journal of Biomechanics, 2015

The atherosclerosis disease is the most prevalent illness that occurs in large or medium size art... more The atherosclerosis disease is the most prevalent illness that occurs in large or medium size arteries. The most important consequence of this disease is creation of arterial platelets in places where in addition to artery damages; the density of materials such as low density lipoprotein (LDL) is being increased. The produced platelets not only block appropriate blood delivery to downstream fibers but also in advanced stages, rubbing or tearing platelet could bring about clot and eventually heart or brain stroke. In this research, in order to review the procedure of LDLs accumulation within lumens and arterial wall, numerical simulation of LDL particles mass transport by using several layer model and diffusion coefficient depending on shear rate are used. Arteries' walls are assumed to be porous and rigid. In this study, Navier-Stokes equations, mass transport, and Darsi have been solved by numerical methods with regarding to non-Newtonian behavior of blood in lumens and different layers of vessel's wall. In this article, the impacts of diffusion coefficient being constant or variable, impact of non-Newtonian behavior of blood, impact of non-Newtonian behavior of plasma and impact of blood pressure on the amount of LDL accumulation in lumen and layers of carotid artery are reviewed. The results indicate that diffusion coefficient variation in arterial lumen and non-Newtonian behavior of plasma within the arterial wall could affect significantly on LDL accumulation. In addition, increasing blood pressure not only increases LDL accumulation on interface of blood and arterial wall but also increases the accumulation within arterial wall layers and consequently the artery is more susceptible to atherosclerosis development.

International Journal of Modern Physics C, 2016

Blood non-Newtonian behavior on low-density lipoproteins (LDL) accumulation is analyzed numerical... more Blood non-Newtonian behavior on low-density lipoproteins (LDL) accumulation is analyzed numerically, while fluid-multilayered arteries are adopted for nonstenotic and 30%–60% symmetrical stenosed models. Present model considers non-Newtonian effects inside the lumen and within arterial layers simultaneously, which has not been examined in previous studies. Navier–Stokes equations are solved along with the mass transport convection–diffusion equations and Darcy’s model for species transport inside the luminal flow and across wall layers, respectively. Carreau model for the luminal flow and the modified Darcy equation for the power-law fluid within arterial layers are employed to model blood rheological characteristics, appropriately. Results indicate that in large arteries with relatively high Reynolds number Newtonian model estimates LDL concentration patterns well enough, however, this model seriously incompetent for regions with low WSS. Moreover, Newtonian model for plasma undere...

Annals of Biomedical Engineering, 2021

Atrial fibrillation (AF) can alter intra-cardiac flow and cardiac output that subsequently affect... more Atrial fibrillation (AF) can alter intra-cardiac flow and cardiac output that subsequently affects aortic flow circulation. These changes may become more significant where they occur concomitantly with ageing. Aortic ageing is accompanied with morphological changes such as dilation, lengthening, and arch unfolding. While the recognition of AF mechanism has been the subject of numerous studies, less focus has been devoted to the aortic circulation during the AF and there is a lack of such investigation at different ages. The current work aims to address the present gap. First, we analyse aortic flow distribution in three configurations, which attribute to young, middle and old people, using geometries constructed via clinical data. We then introduce two transient inlet flow conditions representative of key AF-associated defects. Results demonstrate that both AF and ageing negatively affect flow circulation. The main consequence of concomitant occurrence is enhancement of endothelial ...

20th Annual International …, 2012

The bubble coalescence is discussed in many chemical and metallurgical phenomena. In this paper, ... more The bubble coalescence is discussed in many chemical and metallurgical phenomena. In this paper, the coalescence process of two bubbles moving in a cylindrical tube is studied using both 2D and 3D numerical simulations. The Navier-Stokes equations along with an equation for the interface advection by the Volume-of-Fluid (VOF) method are solved. The results are compared with experimental data reported in the literatures. Simulations are performed for various cases with different configurations of the two bubbles. First, the coaxial bubble motion is studied. The Reynolds number, the density ratio and the viscosity ratio are held constant. The results show that by increasing the Bond number the coalescence time decreases and the leading bubble reveals a more concave interface. Both of these effects make the two bubbles to coalesce faster. Next, the motion of the two bubbles rising side-by-side is studied. On the basis of different Weber numbers based on the approach velocity of the bubbles and the rise velocity, either coalescence or separation will occur.

Emerging Trends in Mechatronics, 2023

Emerging Trends in Mechatronics

Lumped (zero-dimensional) technique is a robust and widely used approach to mathematically model ... more Lumped (zero-dimensional) technique is a robust and widely used approach to mathematically model and explore bulk behaviour of different physical phenomena in a lower expense. In modelling of cardio/cerebrovascular fluid dynamics, this technique facilitates the assessment of relevant metrics such as flow, pressure, and temperature at different locations over a large network/domain. Furthermore, they can be employed as boundary conditions in multiscale modelling of physiological flows. In this methodology paper, a lumped model for the cardiovascular flow simulation along with a two-node thermoregulation model are employed. The lumped models are built upon previous studies and are amended appropriately to focus on cardiac function. The output of the coupled model can either be used for assessing the cardiac function in different physiological conditions or it can provide the input data for other investigations. Noteworthy to mention that, the present model has been specifically develo...

دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا يارب : Please cite this article using: A. Deyranlo... more دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا يارب : Please cite this article using: A. Deyranlou, H. Niazmand, M.R. Sadeghi, Investigation of effective parameters on accumulation of low-density lipoproteins based on the multilayer wall of the carotid artery , Modares Mechanical Engineering, Vol. 14, No. 4, pp. 27-36, 2014 (In Persian) نیئتورپوپیل تشابنا رب رثؤم لماوع یسررب لدم يانبم رب نییاپ هتیسناد اب اه هیلا دنچ دیتوراک نایرش هراوید

دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا يارب : Please cite this article using: A. Deyranlo... more دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا يارب : Please cite this article using: A. Deyranlou, H. Niazmand, Y. Mesri, Blood pulsatile effect on LDL mass transport in a multilayered carotid artery with atherosclerotic plaques, Modares Mechanical Engineering, Vol. 14, No. 7, pp. 17-26, 2014 (In Persian) گرخرس رد نییاپ هتیسناد اب نیئتورپوپیل تارذ مرج لاقتنا رب نوخ ینابرض نایرج ریثات كلاپ ياراد هیلادنچ هراوید اب دیتوراک کیتورلکسورتآ ياه

Frontiers in Bioengineering and Biotechnology, 2020

Congenital heart disease (CHD) is the most common birth defect globally and coarctation of the ao... more Congenital heart disease (CHD) is the most common birth defect globally and coarctation of the aorta (CoA) is one of the commoner CHD conditions, affecting around 1/1800 live births. CoA is considered a CHD of critical severity. Unfortunately, the prognosis for a child born in a low and lower-middle income country (LLMICs) with CoA is far worse than in a high-income country. Reduced diagnostic and interventional capacities of specialists in these regions lead to delayed diagnosis and treatment, which in turn lead to more cases presenting at an advanced stage. Computational fluid dynamics (CFD) is an important tool in this context since it can provide additional diagnostic data in the form of hemodynamic parameters. It also provides an in silico framework, both to test potential procedures and to assess the risk of further complications arising post-repair. Although this concept is already in practice in high income countries, the clinical infrastructure in LLMICs can be sparse, and access to advanced imaging modalities such as phase contrast magnetic resonance imaging (PC-MRI) is limited, if not impossible. In this study, a pipeline was developed in conjunction with clinicians at the Red Cross War Memorial Children's Hospital, Cape Town and was applied to perform a patient-specific CFD study of CoA. The pipeline uses data acquired from CT angiography and Doppler transthoracic echocardiography (both much more clinically available than MRI in LLMICs), while segmentation is conducted via SimVascular and simulation is realized using OpenFOAM. The reduction in cost through use of open-source software and the use of broadly available imaging modalities

International Journal of Modern Physics C, 2020

Over the past few decades, different therapeutic methods for the treatment of intracranial aneury... more Over the past few decades, different therapeutic methods for the treatment of intracranial aneurysms have been developed. During recent years, novel standalone intrasaccular Woven EndoBridge (WEB) technique has paved the way for efficient therapy and reduced some deficiencies in prior procedures. Blood hemodynamics plays a crucial role in occurrence and perpetuating of aneurysm; therefore, understanding of relevant parameters can lead to a better treatment and evolution of design. Objectively, this paper has established the first mathematical framework to explore hemodynamic parameters for WEB-treated saccular aneurysms by employing Computational Fluid Dynamics (CFD). Two ideal models of artery — one is suffered by a bifurcation aneurysm at Basilar Artery (BA) and another Posterior Cerebral Artery (PCA) aneurysm — are selected. Simulations are performed for an untreated and three WEB-treated aneurysms by Dual Layer (DL), Single Layer (SL) and Single Layer Sphere (SLS) WEBs. Results ...

Annals of Biomedical Engineering, 2020

Atrial fibrillation (AF) is the most common type of arrhythmia, which undermines cardiac function... more Atrial fibrillation (AF) is the most common type of arrhythmia, which undermines cardiac function. Atrial fibrillation is a multi-facet malady and it may occur as a result of other diseases or it may trigger other problems. One of the main complications of AF is stroke due to the possibility of clot formation inside the atrium. However, the possibility of stroke occurrence due to the AF and the location from which an embolus dispatches are subject of debate. Another hypothesis about the embolus formation during AF is thrombus formation in aorta and carotid arteries, embolus detachment and its movement. To investigate the possibility of the latter postulation, the current work suggests a parametric study to quantify the sensitivity of aortic flow to four common AF traits including lack of atrial kick, atrial remodelling, left ventricle systolic dysfunction, and high frequency fibrillation. The simulation was carried out by coupling several in-house codes and ANSYS-CFX module. The res...

European Heart Journal, 2019

Background Tetralogy of Fallot (ToF) and coarctation of the aorta (CoA) each constitute approxima... more Background Tetralogy of Fallot (ToF) and coarctation of the aorta (CoA) each constitute approximately 7% of congenital heart disease (CHD) births worldwide. Compared to developed countries, developing countries have a disparate level of access to prompt diagnosis and treatment for these diseases. Computational fluid dynamics (CFD) approaches implemented on routinely available non-invasive imaging data may yield low-cost improvements to the management of these patients. Purpose The purpose of this research is to develop a patient-specific computational pipeline that allows the modelling of blood flow in diseased arteries of patients suffering from ToF and CoA. The project aims to prove the feasible use of broadly available imaging techniques - CT angiograms (CTA) and echocardiographs (echo) - for achieving this in low-to-middle income countries. The capability of the pipeline will be demonstrated through a qualitative study of the effects of different systemic to pulmonary shunt conf...

This paper presents a numerical study of the gas–powder flow in a typical Lapple cyclone with div... more This paper presents a numerical study of the gas–powder flow in a typical Lapple cyclone with division of gas and particle flow in a vortex finder. The Navier-Stokes equations along with the RNG k-ε turbulent model are solved numerically. The separation efficiency and the trajectory of particles are simulated and the effects of the particle size on the separation efficiency and the particle residence time are investigated. The effect of the particle density on the particle size in the range which results 100% cyclone separation efficiency and particle residensce time is investigated. Large particles generally have a higher concentration in the wall region and small particles have a higher concentration in the inner vortex region. Particles enter from different sides give different separation efficiency and trajectory. A particle with a size exceeding a critical diameter or a critical density would stagnate on the wall of the cyclone’s cone. This phenomenon is regarded as a main reason for the deposition on the inner conical surface in such cyclones used in cement industry.

مشاهدات زیادی نشان داده‌اند که بیماری تصلب شراین در عروق خمیده و محل چند شاخگی عروق که همودینامیک... more مشاهدات زیادی نشان داده‌اند که بیماری تصلب شراین در عروق خمیده و محل چند شاخگی عروق که همودینامیک پیچیده دارند، اتفاق می‌افتد. معمولاً تنش‌های برشی نوسانی بزرگ یا کوچکی در این نواحی در دیواره عروق ایجاد می¬شود در مطالعه¬ی حاضر جریان سه¬بعدی خون، همراه با پروفیل سرعت و فشار واقعی در شریان کاروتید داخلی با سه هندسه¬ی واقعی متفاوت و با استفاده از نرم‌افزار اپن فوم مورد مطالعه قرارگرفته است. سه مدلی که در آن‌ها تنش برشی دیواره حائز اهمیت است، مشخص گردیده و خطر گرفتی در این نواحی با توجه به ‌سرعت محوری و مقادیر تنش برشی دیواره مورد مطالعه قرارگرفته است. حل عددی توسط مقایسه با نتایج آزمایشگاهی درون خم 90 درجه اعتبار سنجی شده است. نظریه محل گرفتگی در سه هندسه¬ی مختلف کاروتید داخلی بررسی و مشخص ¬شده که شکل هندسی عروق تأثیر بسزایی در ایجاد گرفتگی¬ها دارند. احتمال شروع این بیماری در خم¬های بزرگ، بیشتر است؛ زیرا که در این نواحی تنش برشی دیواره کوچک‌تر و شاخص تنش نوسانی بزرگ می¬شود در نتیجه مطالعه¬ی هندسی امکان تشخیص مکان¬های مستعد گرفتگی را فراهم می¬آورد.

Journal of Biomechanics, 2015

The atherosclerosis disease is the most prevalent illness that occurs in large or medium size art... more The atherosclerosis disease is the most prevalent illness that occurs in large or medium size arteries. The most important consequence of this disease is creation of arterial platelets in places where in addition to artery damages; the density of materials such as low density lipoprotein (LDL) is being increased. The produced platelets not only block appropriate blood delivery to downstream fibers but also in advanced stages, rubbing or tearing platelet could bring about clot and eventually heart or brain stroke. In this research, in order to review the procedure of LDLs accumulation within lumens and arterial wall, numerical simulation of LDL particles mass transport by using several layer model and diffusion coefficient depending on shear rate are used. Arteries' walls are assumed to be porous and rigid. In this study, Navier-Stokes equations, mass transport, and Darsi have been solved by numerical methods with regarding to non-Newtonian behavior of blood in lumens and different layers of vessel's wall. In this article, the impacts of diffusion coefficient being constant or variable, impact of non-Newtonian behavior of blood, impact of non-Newtonian behavior of plasma and impact of blood pressure on the amount of LDL accumulation in lumen and layers of carotid artery are reviewed. The results indicate that diffusion coefficient variation in arterial lumen and non-Newtonian behavior of plasma within the arterial wall could affect significantly on LDL accumulation. In addition, increasing blood pressure not only increases LDL accumulation on interface of blood and arterial wall but also increases the accumulation within arterial wall layers and consequently the artery is more susceptible to atherosclerosis development.

International Journal of Modern Physics C, 2016

Blood non-Newtonian behavior on low-density lipoproteins (LDL) accumulation is analyzed numerical... more Blood non-Newtonian behavior on low-density lipoproteins (LDL) accumulation is analyzed numerically, while fluid-multilayered arteries are adopted for nonstenotic and 30%–60% symmetrical stenosed models. Present model considers non-Newtonian effects inside the lumen and within arterial layers simultaneously, which has not been examined in previous studies. Navier–Stokes equations are solved along with the mass transport convection–diffusion equations and Darcy’s model for species transport inside the luminal flow and across wall layers, respectively. Carreau model for the luminal flow and the modified Darcy equation for the power-law fluid within arterial layers are employed to model blood rheological characteristics, appropriately. Results indicate that in large arteries with relatively high Reynolds number Newtonian model estimates LDL concentration patterns well enough, however, this model seriously incompetent for regions with low WSS. Moreover, Newtonian model for plasma undere...

Annals of Biomedical Engineering, 2021

Atrial fibrillation (AF) can alter intra-cardiac flow and cardiac output that subsequently affect... more Atrial fibrillation (AF) can alter intra-cardiac flow and cardiac output that subsequently affects aortic flow circulation. These changes may become more significant where they occur concomitantly with ageing. Aortic ageing is accompanied with morphological changes such as dilation, lengthening, and arch unfolding. While the recognition of AF mechanism has been the subject of numerous studies, less focus has been devoted to the aortic circulation during the AF and there is a lack of such investigation at different ages. The current work aims to address the present gap. First, we analyse aortic flow distribution in three configurations, which attribute to young, middle and old people, using geometries constructed via clinical data. We then introduce two transient inlet flow conditions representative of key AF-associated defects. Results demonstrate that both AF and ageing negatively affect flow circulation. The main consequence of concomitant occurrence is enhancement of endothelial ...

20th Annual International …, 2012

The bubble coalescence is discussed in many chemical and metallurgical phenomena. In this paper, ... more The bubble coalescence is discussed in many chemical and metallurgical phenomena. In this paper, the coalescence process of two bubbles moving in a cylindrical tube is studied using both 2D and 3D numerical simulations. The Navier-Stokes equations along with an equation for the interface advection by the Volume-of-Fluid (VOF) method are solved. The results are compared with experimental data reported in the literatures. Simulations are performed for various cases with different configurations of the two bubbles. First, the coaxial bubble motion is studied. The Reynolds number, the density ratio and the viscosity ratio are held constant. The results show that by increasing the Bond number the coalescence time decreases and the leading bubble reveals a more concave interface. Both of these effects make the two bubbles to coalesce faster. Next, the motion of the two bubbles rising side-by-side is studied. On the basis of different Weber numbers based on the approach velocity of the bubbles and the rise velocity, either coalescence or separation will occur.