Lactation in the Human Breast From a Fluid Dynamics Point of View

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
S. Negin Mortazavi ◽  
Donna Geddes ◽  
Fatemeh Hassanipour
Keyword(s):  
Fluid Dynamics ◽  
Clinical Data ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Geometric Model ◽  
Milk Intake ◽  
Vacuum Pressure ◽  
Cfd Modeling ◽  
Human Breast ◽  
Milk Flow

This study is a collaborative effort among lactation specialists and fluid dynamic engineers. The paper presents clinical results for suckling pressure pattern in lactating human breast as well as a 3D computational fluid dynamics (CFD) modeling of milk flow using these clinical inputs. The investigation starts with a careful, statistically representative measurement of suckling vacuum pressure, milk flow rate, and milk intake in a group of infants. The results from clinical data show that suckling action does not occur with constant suckling rate but changes in a rhythmic manner for infants. These pressure profiles are then used as the boundary condition for the CFD study using commercial ansys fluent software. For the geometric model of the ductal system of the human breast, this work takes advantage of a recent advance in the development of a validated phantom that has been produced as a ground truth for the imaging applications for the breast. The geometric model is introduced into CFD simulations with the aforementioned boundary conditions. The results for milk intake from the CFD simulation and clinical data were compared and cross validated. Also, the variation of milk intake versus suckling pressure are presented and analyzed. Both the clinical and CFD simulation show that the maximum milk flow rate is not related to the largest vacuum pressure or longest feeding duration indicating other factors influence the milk intake by infants.

scholarly journals Biomagnetic Monitoring vs. CFD Modeling: A Real Case Study of Near-Source Depositions of Traffic-Related Particulate Matter along a Motorway

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1285
Author(s):  
Sarah Letaïef ◽  
Pierre Camps ◽  
Thierry Poidras ◽  
Patrick Nicol ◽  
Delphine Bosch ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particulate Matter ◽  
Cfd Simulation ◽  
Low Cost ◽  
Precast Concrete ◽  
Cfd Modeling ◽  
Concrete Wall ◽  
Fluorescence Measurements ◽  
Computational Fluid Dynamics Cfd

A test site located along a 12-lane motorway east of Montpellier, France, is used to evaluate the potential of biomagnetic monitoring on traffic-related particulate matter (PM) to parametrize a computational fluid dynamics (CFD) simulation of the local airflow. Two configurations were established on the site with three vegetated flat-top earth berms of a basic design, and a fourth one was located windward to the traffic roofed with a 4-m-high precast concrete wall. As a first step, PM deposition simultaneously on plant leaves, on low-cost passive artificial filters, and on soils was estimated from proxies supplied by magnetic and X-ray fluorescence measurements on both sides of the motorway. These latter revealed that traffic-related pollutants are present on soils samples highlighted with a clear fingerprint of combustion residues, and wears of breaks, vehicles, and highway equipment. Maximum PM accumulations were detected in the lee of the berm–wall combination, while no significant deposition was observed on both sides of the flat-top earth berms. These results are in line with measurements from PM µ-sensors operated by the regional state-approved air quality agency. Finally, we compared the experimental measurements with the outcomes of a computational fluid dynamics (CFD) modeling based on the Reynolds-Averaged Navier–Stokes (RANS) equations that consider the traffic-induced momentum and turbulence. The CFD modeling matches the experimental results by predicting a recirculated flow in the near wake of the berm–wall combination that enhances the PM concentration, whereas the flat-top berm geometry does not alter the pollutants’ transport and indeed contributes to their atmospheric dispersion.

scholarly journals Noninvasive estimation of pharyngeal airway resistance and compliance in children based on volume-gated dynamic MRI and computational fluid dynamics

2011 ◽  
Vol 111 (6) ◽  
pp. 1819-1827 ◽  
Author(s):  
Steven C. Persak ◽  
Sanghun Sin ◽  
Joseph M. McDonough ◽  
Raanan Arens ◽  
David M. Wootton
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Rate ◽  
Magnetic Resonance Images ◽  
Cfd Modeling ◽  
Tidal Breathing ◽  
Upper Airways ◽  
Pharyngeal Airway ◽  
Airway Collapse ◽  
Obstructive Sleep

Computational fluid dynamics (CFD) analysis was used to model the effect of collapsing airway geometry on internal pressure and velocity in the pharyngeal airway of three sedated children with obstructive sleep apnea syndrome (OSAS) and three control subjects. Model geometry was reconstructed from volume-gated magnetic resonance images during normal tidal breathing at 10 increments of tidal volume through the respiratory cycle. Each geometry was meshed with an unstructured grid and solved using a low-Reynolds number k-ω turbulence model driven by flow data averaged over 12 consecutive breathing cycles. Combining gated imaging with CFD modeling created a dynamic three-dimensional view of airway anatomy and mechanics, including the evolution of airway collapse and flow resistance and estimates of the local effective compliance. The upper airways of subjects with OSAS were generally much more compliant during tidal breathing. Compliance curves (pressure vs. cross-section area), derived for different locations along the airway, quantified local differences along the pharynx and between OSAS subjects. In one subject, the distal oropharynx was more compliant than the nasopharynx (1.028 vs. 0.450 mm2/Pa) and had a lower theoretical limiting flow rate, confirming the distal oropharynx as the flow-limiting segment of the airway in this subject. Another subject had a more compliant nasopharynx (0.053 mm2/Pa) during inspiration and apparent stiffening of the distal oropharynx (C = 0.0058 mm2/Pa), and the theoretical limiting flow rate indicated the nasopharynx as the flow-limiting segment. This new method may help to differentiate anatomical and functional factors in airway collapse.

Optimization of Quench Tank Structure Based on CFD Simulation

2006 ◽  
Vol 118 ◽  
pp. 363-368 ◽  
Author(s):  
Nai Lu Chen ◽  
Wei Min Zhang ◽  
Qiang Li ◽  
Chang Yin Gao ◽  
Bo Liao ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Draft Tube ◽  
Structure Design ◽  
Rate Distribution ◽  
Large Size ◽  
Solid Foundation ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

In order to investigate the flow rate distribution and improve the flow rate uniformity of the quenchant in a quench tank, the ultrasonic Doppler velocimeter (UDV) was used to measure the flow rate of quenchant with agitation, and then a computational fluid dynamics (CFD) simulation was carried out to simulate the flow rate distribution without / with flow baffles. According to the CFD simulation results, the structures and positions of flow baffles in the draft-tube were optimized to obtain the uniform flow rate distribution in the quench zone, which were verified by experiments as well. The simulation and experimental results show that the UDV is suitable for measuring the flow rate of a large-size quench tank. This research provided a solid foundation for optimizing the structure design of flow baffles in production quench tanks.

Computational Fluid Dynamics Simulation of Flow Mixing in Tunnel Kilns by Air Side Injection

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Adnan Ghareeb Tuaamah Al-Hasnawi ◽  
H. A. Refaey ◽  
T. Redemann ◽  
M. Attalla ◽  
E. Specht
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Maximum Error ◽  
Dynamics Simulation ◽  
Maximum Temperature ◽  
Injection Velocity ◽  
Maximum Temperature Difference ◽  
Mixing Quality

The mixing of the two axial flows through the ware and through the gap between ware and walls using side nozzles in the preheating zone of tunnel kiln is investigated. The three-dimensional temperature field in the cross section between the two cars is calculated using the computational fluid dynamics (CFD) tool fluent. The mixing quality is evaluated using contours, the frequency of temperature distribution, and the maximum temperature difference. The influence on the mixing behavior of injection flow rate, injection velocity, nozzles position, and nozzle number has been analyzed. The results show that using two nozzles is more effective than one nozzle if the nozzles are installed at the opposite side walls with high vertical distance. The mixing quality increases strongly until an impulse flow rate (IFR) of about 4 N. For higher values, the influence becomes relatively low. The results for the mixing temperature obtained through CFD simulation compared with analytical results show a good agreement with maximum error of 0.5%.

scholarly journals Computational fluid dynamics analysis of flow through immobilized catalyzed packed bed reactor for removal of 4-chlorophenol from wastewater

2019 ◽  
Vol 25 (6) ◽  
pp. 878-889 ◽  
Author(s):  
Sudhansu Sandhibigraha ◽  
Soumya Sasmal ◽  
Tarun Kanti Bandyopadhyay ◽  
Biswanath Bhunia
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Inlet Concentration ◽  
Bed Height ◽  
Fluent Software ◽  
Flow Through

The computational fluid dynamics (CFD) simulation of the packed bed reactor (PBR) was carried out using ANSYS Fluent software. The various process parameters, such as inlet concentration of 4-chlorophenol (4-CP), flow rate, bed height, and porosity, were optimized to predict maximum biodegradation of 4-CP in immobilized catalyzed PBR. The geometrical mesh of the PBR was constructed using Gambit software, and a mesh size of 236995 was selected from the grid-independent study. A laminar flow model was used to understand the hydrodynamics as well as concentration profile of 4-CP inside the PBR using Fluent software. Through CFD, the effect of the flow rate, inlet concentration, and the bed height and porosity of the immobilized catalyst bed on the static pressure, mass imbalance, velocity, and stress-strain field inside the PBR was visualized. CFD simulation study predicted that maximum biodegradation of 4-CP was found in the presence of 500 mg/L of inlet concentration of 4-CP, 4 mL/min of flow rate, 18 cm of bed height and 0.375 of porosity. An experimental study was conducted for wastewater flow through the <i>B. subtilis MF447840.1</i> immobilized catalyzed PBR to remove the 4-CP in the laminar flow region. It was evident that CFD simulated results agreed well with experimental values.

scholarly journals Computational Simulations of the 4-D Micro-Circulatory Network in Zebrafish Tail Amputation and Regeneration

2021 ◽  
Author(s):  
Mehrdad Roustaei ◽  
Kyung In Baek ◽  
Zhaoqiang Wang ◽  
Susana Cavallero ◽  
Sandro Satta ◽  
...  
Keyword(s):  
Flow Rate ◽  
Cfd Simulation ◽  
Fluorescent Protein ◽  
Cfd Modeling ◽  
Endothelial Lining ◽  
Zebrafish Model ◽  
Cardinal Vein ◽  
Vascular Regeneration ◽  
Computational Fluid Dynamics Cfd ◽  
Green Fluorescent

AbstractWall shear stress (WSS) in the micro-vasculature contributes to biomechanical cues that regulate mechanotransduction underlying vascular development, regeneration, and homeostasis. We hereby elucidate the interplay between hemodynamic shear forces and luminal remodeling in response to vascular injury and regeneration in the zebrafish model of tail amputation. Using the transgenic Tg(fli1:eGFP; Gata1:ds-red) line, we were able to track the enhanced green-fluorescent protein (eGFP)-labeled endothelial lining of the 3-D microvasculature for post-image segmentation and reconstruction of fluid domain for computational fluid dynamics (CFD) simulation. At 1 day post amputation (dpa), dorsal aorta (DA) and posterior cardinal vein (PCV) were severed, and vasoconstriction developed in the dorsal longitudinal anastomotic vessel (DLAV) with a concomitant increase in WSS in the segmental vessels (SV) proximal to the amputation site and a decrease in WSS in SVs distal to amputation. Simultaneously, we observed angiogenesis commencing at the tips of the amputated DLAV and PCV where WSS was minimal in the absence of blood flow. At 2 dpa, vasodilation occurred in a pair of SVs proximal to amputation, resulting in increased flow rate and WSS, whereas in the SVs distal to amputation, WSS normalized to the baseline. At 3 dpa, the flow rate in the arterial SV proximal to amputation continued to rise and merged with DLAV that formed a new loop with PCV. Thus, our CFD modeling uncovered a well-coordinated micro-vascular adaptation process following tail amputation, accompanied by the rise and fall of WSS and dynamic changes in flow rate during vascular regeneration.

Fluid-Structure Interaction Simulation of Lactating Human Breast

2019 ◽  
Author(s):  
Jamasp Azarnoosh ◽  
Fatemeh Hassanipour
Keyword(s):  
Flow Behavior ◽  
Fluid Structure Interaction ◽  
Vacuum Pressure ◽  
Ultrasound Images ◽  
Human Breast ◽  
Fluid Structure ◽  
Ductal System ◽  
Structure Interaction ◽  
Milk Flow ◽  
Interaction Simulation

Abstract Extracting milk during breastfeeding is not only caused by intra-oral vacuum pressure by the infant suckling but also is the periodic motion of the infant’s jaw, which is the focus of this study. A Fluid-structure interaction simulation provides a better understanding of the milk flow behavior in the human breast ductal system as the breast interacts with the infant’s oral cavity and jaws. Simulations were performed from the instance of latching and continued for two cycles of periodic tongue motion. The negative vacuum pressure profile was measured from the clinical data and applied in the simulation. The nipple dimensions were obtained using ultrasound images and used as boundary conditions in the simulation. The effect of vacuum pressure and the peripheral pressure on the milk flow behavior in breast ductal system were studied individually. It was observed that the deformation of the ductal system has a critical impact on milk flow behavior and the amount of expressed milk.

Eulerian-Eulerian modelling and computational fluid dynamics simulation of wire mesh demisters in MSF plants

2014 ◽  
Vol 31 (7) ◽  
pp. 1242-1260 ◽  
Author(s):  
Hala Al-Fulaij ◽  
Andrea Cipollina ◽  
Giorgio Micale ◽  
Hisham Ettouney ◽  
David Bogle
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Wire Mesh ◽  
Dynamics Simulation ◽  
Cfd Modeling ◽  
Computational Domain ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Plant Data

Purpose – The purpose of this study is to focus on simulation of wire mesh demisters in multistage flash desalination (MSF) plants. The simulation is made by the use of computational fluid dynamics (CFD) software. Design/methodology/approach – A steady state and two-dimensional (2D) model was developed to simulate the demister. The model employs an Eulerian-Eulerian approach to simulate the flow of water vapor and brine droplets in the demister. The computational domain included three zones, which are the vapor space above and below the demister and the demister. The demister zone was modeled as a tube bank arrange or as a porous media. Findings – Sensitivity analysis of the model showed the main parameters that affect demister performance are the vapor velocity and the demister permeability. On the other hand, the analysis showed that the vapor temperature has no effect on the pressure drop across the demister. Research limitations/implications – The developed model was validated against previous literature data as well as real plant data. The analysis shows good agreement between model prediction and data. Originality/value – This work is the first in the literature to simulate the MSF demister using CFD modeling. This work is part of a group effort to develop a comprehensive CFD simulation for the entire flashing stage of the MSF process, which would provide an extremely efficient and inexpensive design and simulation tool to the desalination community.

scholarly journals Computational Fluid Dynamics Modeling of Rotating Annular VUV/UV Photoreactor for Water Treatment

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 79
Author(s):  
Minghan Luo ◽  
Wenjie Xu ◽  
Xiaorong Kang ◽  
Keqiang Ding ◽  
Taeseop Jeong
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Water Treatment ◽  
Cfd Modeling ◽  
Flow Mode ◽  
Oh Radicals ◽  
Dynamics Modeling ◽  
Rotational Movement ◽  
Contaminant Degradation ◽  
Wide Range

The ultraviolet photochemical degradation process is widely recognized as a low-cost, environmentally friendly, and sustainable technology for water treatment. This study integrated computational fluid dynamics (CFD) and a photoreactive kinetic model to investigate the effects of flow characteristics on the contaminant degradation performance of a rotating annular photoreactor with a vacuum-UV (VUV)/UV process performed in continuous flow mode. The results demonstrated that the introduced fluid remained in intensive rotational movement inside the reactor for a wide range of inflow rates, and the rotational movement was enhanced with increasing influent speed within the studied velocity range. The CFD modeling results were consistent with the experimental abatement of methylene blue (MB), although the model slightly overestimated MB degradation because it did not fully account for the consumption of OH radicals from byproducts generated in the MB decomposition processes. The OH radical generation and contaminant degradation efficiency of the VUV/UV process showed strong correlation with the mixing level in a photoreactor, which confirmed the promising potential of the developed rotating annular VUV reactor in water treatment.

scholarly journals Geometrical Optimization of a Venturi-Type Microbubble Generator Using CFD Simulation and Experimental Measurements

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 4
Author(s):  
Dillon Alexander Wilson ◽  
Kul Pun ◽  
Poo Balan Ganesan ◽  
Faik Hamad
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Air Flow ◽  
Bubble Diameter ◽  
Diameter Ratio ◽  
Experimental Measurements ◽  
Cfd Model ◽  
Flow Rates ◽  
Throat Diameter

Microbubble generators are of considerable importance to a range of scientific fields from use in aquaculture and engineering to medical applications. This is due to the fact the amount of sea life in the water is proportional to the amount of oxygen in it. In this paper, experimental measurements and computational Fluid Dynamics (CFD) simulation are performed for three water flow rates and three with three different air flow rates. The experimental data presented in the paper are used to validate the CFD model. Then, the CFD model is used to study the effect of diverging angle and throat length/throat diameter ratio on the size of the microbubble produced by the Venturi-type microbubble generator. The experimental results showed that increasing water flow rate and reducing the air flow rate produces smaller microbubbles. The prediction from the CFD results indicated that throat length/throat diameter ratio and diffuser divergent angle have a small effect on bubble diameter distribution and average bubble diameter for the range of the throat water velocities used in this study.

Sign in / Sign up

Export Citation Format

Share Document