scholarly journals The Effect of Parameter Variation on Spiral Flow Inducing Cannula Performances

2021 ◽  
Vol 2071 (1) ◽  
pp. 012011
Author(s):  
F Muzamil Mustafa ◽  
N S Shafii ◽  
M R Abdul Kadir ◽  
M N Che Aziz ◽  
K Osman ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Shear Stress ◽  
Considerable Effect ◽  
Selection Method ◽  
Parameter Variation ◽  
Hemodynamic Effects ◽  
Spiral Flow ◽  
Flow Parameters ◽  
Outflow Velocity ◽  
Computational Fluid Dynamics Cfd

Abstract Spiral flow-inducing cannula has been shown in previous research to exhibit a considerable effect on flow hemodynamic. However, there is still room for improvement. In this study, several design variations were tested to determine which variants were the best in terms of flow reduction. Computational Fluid Dynamics (CFD) software was used to simulate flow within a spiral flow-inducing cannula with several variations from chamber width and angle differences. The variants were compared against each other by using several flow parameters and a selection method was employed to determine which model was the best. It was found that a variant that has the widest chamber (14 mm) and biggest angle opening (70°) from the chamber to the cannula tube was the best in several parameters, and as such was chosen as the best variant. When compared with the standard straight cannula, the reduction in flow output was recorded to be 30% which is deemed significantly. In conclusion, spiral flow cannula recorded better hemodynamic effects with lower outflow velocity and wall shear stress value.

Efficiency prediction for storage chambers using computational fluid dynamics

1996 ◽  
Vol 33 (9) ◽  
pp. 163-170 ◽  
Author(s):  
Virginia R. Stovin ◽  
Adrian J. Saul
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Particle Tracking ◽  
Critical Value ◽  
Complex Geometries ◽  
Bed Shear Stress ◽  
Breadth Ratio ◽  
Computational Fluid Dynamics Cfd ◽  
Simulated Flow

Research was undertaken in order to identify possible methodologies for the prediction of sedimentation in storage chambers based on computational fluid dynamics (CFD). The Fluent CFD software was used to establish a numerical model of the flow field, on which further analysis was undertaken. Sedimentation was estimated from the simulated flow fields by two different methods. The first approach used the simulation to predict the bed shear stress distribution, with deposition being assumed for areas where the bed shear stress fell below a critical value (τcd). The value of τcd had previously been determined in the laboratory. Efficiency was then calculated as a function of the proportion of the chamber bed for which deposition had been predicted. The second method used the particle tracking facility in Fluent and efficiency was calculated from the proportion of particles that remained within the chamber. The results from the two techniques for efficiency are compared to data collected in a laboratory chamber. Three further simulations were then undertaken in order to investigate the influence of length to breadth ratio on chamber performance. The methodology presented here could be applied to complex geometries and full scale installations.

CFD Study on Effect of Branch Sizes in Human Coronary Arteries

2011 ◽  
Author(s):  
Liza Shrestha ◽  
Justin Garvin ◽  
Richard W. Downe ◽  
Milan Sonka ◽  
Andreas Wahle ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Coronary Artery Disease ◽  
Blood Flow ◽  
Shear Stress ◽  
Causes Of Death ◽  
Developed Countries ◽  
Unidirectional Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Artery Disease ◽  
Blood Flow Patterns

Coronary Artery Disease (CAD) is one of the leading causes of death in developed countries. The link between Wall Shear Stress (WSS) and CAD development is well established, with studies indicating the accumulation of lesions in regions of low WSS, flow separation, and in the regions where there is departure from axially aligned unidirectional flow [5]. It has been well established that blood flow patterns are highly affected by branch flows, as bifurcations are one of the leading locations of plaque accumulation [5]. Computational fluid dynamics (CFD) is an important tool for quantifying hemodynamics.

The Influence of Pulmonary Hemodynamics on Right Ventricular Function in Pulmonary Hypertension

2013 ◽  
Author(s):  
Vitaly O. Kheyfets ◽  
Lourdes Rios ◽  
Triston Smith ◽  
Theodore Schroeder ◽  
Jeffrey Mueller ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Pulmonary Hypertension ◽  
Shear Stress ◽  
Right Ventricular ◽  
Pulmonary Arteries ◽  
Pulmonary Hemodynamics ◽  
Arterial Hemodynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Pulmonary Arterial ◽  
Rv Function

Pulmonary arterial hypertension (PAH) is a degenerative disease that can lead to substantial morphometric remodeling of the pulmonary arteries. Previous studies have revealed coupling relationships between right ventricular (RV) function and pulmonary arterial hemodynamics. The objective of this study was to utilize computational fluid dynamics (CFD) to estimate spatially averaged Wall Shear Stress (WSS) for patients with PH and explore correlations between hemodynamics metrics and RV function.

scholarly journals A Workflow for Patient-Individualized Virtual Angiogram Generation Based on CFD Simulation

2012 ◽  
Vol 2012 ◽  
pp. 1-24 ◽  
Author(s):  
Jürgen Endres ◽  
Markus Kowarschik ◽  
Thomas Redel ◽  
Puneet Sharma ◽  
Viorel Mihalef ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Blood Flow ◽  
Shear Stress ◽  
Cfd Simulation ◽  
Cerebral Aneurysms ◽  
Patient Specific ◽  
Hemodynamic Parameters ◽  
Risk Of Rupture ◽  
Computational Fluid Dynamics Cfd ◽  
Subsequent Comparison

Increasing interest is drawn on hemodynamic parameters for classifying the risk of rupture as well as treatment planning of cerebral aneurysms. A proposed method to obtain quantities such as wall shear stress, pressure, and blood flow velocity is to numerically simulate the blood flow using computational fluid dynamics (CFD) methods. For the validation of those calculated quantities, virtually generated angiograms, based on the CFD results, are increasingly used for a subsequent comparison with real, acquired angiograms. For the generation of virtual angiograms, several patient-specific parameters have to be incorporated to obtain virtual angiograms which match the acquired angiograms as best as possible. For this purpose, a workflow is presented and demonstrated involving multiple phantom and patient cases.

scholarly journals Investigating the Effect of Heterogeneous Hull Roughness on Ship Resistance Using CFD

2021 ◽  
Vol 9 (2) ◽  
pp. 202
Author(s):  
Soonseok Song ◽  
Yigit Kemal Demirel ◽  
Claire De Marco Muscat-Fenech ◽  
Tonio Sant ◽  
Diego Villa ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Reynolds Number ◽  
Shear Stress ◽  
Flow Characteristics ◽  
Cfd Simulations ◽  
Ship Resistance ◽  
Wigley Hull ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

Research into the effects of hull roughness on ship resistance and propulsion is well established, however, the effect of heterogeneous hull roughness is not yet fully understood. In this study, Computational Fluid Dynamics (CFD) simulations were conducted to investigate the effect of heterogeneous hull roughness on ship resistance. The Wigley hull was modelled with various hull conditions, including homogeneous and heterogeneous hull conditions. The results were compared against existing experimental data and showed a good agreement, suggesting that the CFD approach is valid for predicting the effect of heterogeneous hull roughness on ship resistance. Furthermore, the local distributions of the wall shear stress and roughness Reynolds number on the hull surface were examined to assess the flow characteristics over the heterogeneous hull roughness.

The suitability of CFD in diagnosis and treatment of laryngeal diseases

2020 ◽  
Vol 9 (2) ◽  
pp. 23-26
Author(s):  
Marta Gamrot-Wrzoł ◽  
Magdalena Marków ◽  
Daniel Janecki ◽  
Maciej Misiołek
Keyword(s):  
Fluid Dynamics ◽  
Shear Stress ◽  
Particle Deposition ◽  
Upper Respiratory Tract ◽  
Review Of The Literature ◽  
Laryngeal Diseases ◽  
Stress Changes ◽  
Computational Fluid Dynamics Cfd ◽  
Upper Respiratory ◽  
Cfd Method

Computational Fluid Dynamics (CFD) is a fluid mechanics department that uses numerical methods to solve fluid flow issues. A review of the literature was done as well to summarize the usage of the CFD method in the assessment of airflow through the upper respiratory tract (GDO), especially in the larynx. CFD is now becoming a very useful tool not only for analyzing airflow patterns and mechanism of particle deposition in the larynx, but also for obtaining information on temperature, pressure and shear stress changes in GDO. It is a tool with which one can safely plan surgical treatment as well as predict its potential effects.

scholarly journals Numerical investigation on bottom shear stress induced by flushing gate for sewer cleaning

2019 ◽  
Vol 80 (2) ◽  
pp. 290-299
Author(s):  
Haoming Yang ◽  
David Z. Zhu ◽  
Yiping Zhang ◽  
Yongchao Zhou
Keyword(s):  
Fluid Dynamics ◽  
Shear Stress ◽  
Transient Flow ◽  
Flow Characteristics ◽  
Bottom Shear Stress ◽  
Sewer Pipe ◽  
Storage Volume ◽  
Flow Information ◽  
Computational Fluid Dynamics Cfd ◽  
Flushing Flows

Abstract One of the most common strategies for sewer cleaning is to generate flushing flows using flushing gates to store water in the upstream sewer pipe. Therefore it is important to obtain the flow information on the flushing waves and their eroding effects. In this study, the flow characteristics of the flushing wave and the flushing effect were investigated by a transient flow calculation using a commercial computational fluid dynamics (CFD) code. The values of bottom shear stress were obtained and the effect of several factors are discussed. The water depth and the slope were related to the release rate of the storage volume, while the flushing volume determined the flushing distance at long sewer distances. The initial downstream water level was found to dramatically reduce the flushing effect. Equations based on the storage depth were developed to estimate the flushing effect, and suggestions for the installation and operation of flushing gates are provided.

scholarly journals Diesel Breeding

2002 ◽  
Vol 124 (09) ◽  
pp. 53-53
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Genetic Algorithms ◽  
Diesel Engines ◽  
Fuel Efficiency ◽  
Selection Method ◽  
Engine Emissions ◽  
Engine Design ◽  
Computational Fluid Dynamics Cfd ◽  
Advanced Visualization

This article discusses the various ways of improving the performance of diesel engines. A Wisconsin engineer is making use of computation methods that mimic natural selection—or, in this case, maybe eugenics—to improve the performance of diesel engines. Peter Senecal, a partner with Convergent Thinking in Madison, WI, is using computational fluid dynamics (CFD) advanced visualization, and a selection method using genetic algorithms aimed at reducing engine emissions and enhancing fuel efficiency. He has been looking ahead to 2007, when tighter vehicle emissions requirements take effect. Senecal and two of his partners, Keith Richards and Eric Pomraning, are continuing the research into cleaner and more efficient engines. Findings have helped to optimize engine design for increased efficiency and lower emissions—two areas of great importance to engine manufacturers and environmentalists.

scholarly journals Investigation on the effect of opening position across an isolated building for wind-driven cross ventilation

2021 ◽  
Vol 15 (2) ◽  
pp. 8141-8152
Author(s):  
Lip Kean Moey ◽  
Kar Lit Chan ◽  
Vin Cent Tai ◽  
Tze Fong Go ◽  
Perk Lin Chong
Keyword(s):  
Fluid Dynamics ◽  
Shear Stress ◽  
Indoor Air ◽  
Model Comparison ◽  
Recirculation Zone ◽  
Ventilation Rate ◽  
Air Velocity ◽  
Indoor Airflow ◽  
Building Model ◽  
Computational Fluid Dynamics Cfd

This study investigates the effect of opening position on the indoor airflow of a natural ventilated isolated building model. Furthermore, the opening configuration which generate the highest ventilation is to be determined. Seven different opening configurations were considered by varying the opening position on the windward and leeward walls which include three cases of aligned openings and four non-aligned openings. Models with different opening position were simulated using Computational Fluid Dynamics (CFD) with 3D RANS turbulence model Shear Stress Transport (SST) k- ω. Simulation result indicates the indoor air velocity as well as pressure distribution highly depends on both inlet and outlet opening positioning. Different opening configuration influences the recirculation zone generated within the building model. Comparison shows openings located near the roof generate 6.52% higher ventilation rate compared to openings located near the ground. The study concludes that opening position holds a crucial role in affecting internal airflow pattern, air recirculation and ventilation rate for a natural cross ventilated building.

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