scholarly journals Effect of Longitudinal Variation of Vocal Fold Inner Layer Thickness on Fluid-Structure Interaction During Voice Production

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Weili Jiang ◽  
Qian Xue ◽  
Xudong Zheng
Keyword(s):  
Computational Model ◽  
Layer Thickness ◽  
Vibration Amplitude ◽  
Vocal Fold ◽  
Fluid Structure Interaction ◽  
Thickness Variation ◽  
Longitudinal Variation ◽  
Fluid Structure ◽  
Voice Production ◽  
Structure Interaction

A three-dimensional fluid-structure interaction computational model was used to investigate the effect of the longitudinal variation of vocal fold inner layer thickness on voice production. The computational model coupled a finite element method based continuum vocal fold model and a Navier–Stokes equation based incompressible flow model. Four vocal fold models, one with constant layer thickness and the others with different degrees of layer thickness variation in the longitudinal direction, were studied. It was found that the varied thickness resulted in up to 24% stiffness reduction at the middle and up to 47% stiffness increase near the anterior and posterior ends of the vocal fold; however, the average stiffness was not affected. The fluid-structure interaction simulations on the four models showed that the thickness variation did not affect vibration amplitude, glottal flow rate, and the waveform related parameters. However, it increased glottal angles at the middle of the vocal fold, suggesting that vocal fold vibration amplitude was determined by the average stiffness of the vocal fold, while the glottal angle was determined by the local stiffness. The models with longitudinal variation of layer thickness consumed less energy during the vibrations compared with the constant layer thickness one.

scholarly journals Inhalation Induced Stresses and Flow Characteristics in Human Airways through Fluid-Structure Interaction Analysis

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Kittisak Koombua ◽  
Ramana M. Pidaparti
Keyword(s):  
Computational Model ◽  
Interaction Analysis ◽  
Airway Remodeling ◽  
Fluid Structure Interaction ◽  
Flow Characteristics ◽  
Fluid Structure ◽  
Tissue Properties ◽  
Structure Interaction ◽  
Simulation Results ◽  
Human Airways

Better understanding of stresses and flow characteristics in the human airways is very important for many clinical applications such as aerosol drug therapy, inhalation toxicology, and airway remodeling process. The bifurcation geometry of airway generations 3 to 5 based on the ICRP tracheobronchial model was chosen to analyze the flow characteristics and stresses during inhalation. A computational model was developed to investigate the airway tissue flexibility effect on stresses and flow characteristics in the airways. The finite-element method with the fluid-structure interaction analysis was employed to investigate the transient responses of the flow characteristics and stresses in the airways during inhalation. The simulation results showed that tissue flexibility affected the maximum airflow velocity, airway pressure, and wall shear stress about 2%, 7%, and 6%, respectively. The simulation results also showed that the differences between the orthotropic and isotropic material models on the airway stresses were in the ranges of 25–52%. The results from the present study suggest that it is very important to incorporate the orthotropic tissue properties into a computational model for studying flow characteristics and stresses in the airways.

On the Mechanics of Phonation and Fluid-Structure Interactions in a Three Dimensional Vocal Fold Model

2007 ◽  
Author(s):  
Somesh Khandelwal ◽  
Thomas Siegmund ◽  
Steve H. Frankel
Keyword(s):  
Vibration Amplitude ◽  
Vocal Fold ◽  
Flow Model ◽  
Three Dimensional ◽  
The Self ◽  
Elastic Response ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Laminar Flow Model

It is hypothesized that the characteristics of vocal fold self oscillation is dependent on the nonlinearity of the solid structure i.e. the tissue. Studies of fluid structure interaction are conducted for three dimensional larynx models. Simulations were performed using the codes FLUENT and ABAQUS coupled by the code MpCCI. For the air an unsteady, laminar flow model was considered. Visco-hyperelasticity was used to characterize the solid domain representing the tissue structure. The computational model is used to conduct a parametric study on the self-oscillation response of the model with focus on the influence of the non-linearity in the hyperelastic response. Individual computations were compared by documenting the variation of the total energy of the structure. It is demonstrated that dissipation in the flow as well as the non-linearity in the elastic response all interact to stabilize or destabilize the vibration amplitude.

scholarly journals Adaptive stabilized finite element framework for simulation of vocal fold turbulent fluid-structure interaction

2013 ◽  
Author(s):  
Johan Jansson ◽  
Andreas Holmberg ◽  
Rodrigo Vilela de Abreu ◽  
Cem Degirmenci ◽  
Johan Hoffman ◽  
...  
Keyword(s):  
Finite Element ◽  
Vocal Fold ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Turbulent Fluid ◽  
Stabilized Finite Element ◽  
Structure Interaction

A Computational Model for Analysis of Fluid-Structure Interaction Within Elastomeric Progressing Cavity Pumps

2013 ◽  
Author(s):  
Emilio E. Paladino ◽  
Rairam F.C. Almeida ◽  
Benno W. Assmann ◽  
Joao A. Lima ◽  
Philippe E. Medeiros
Keyword(s):  
Computational Model ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Structure Interaction

scholarly journals Fluid-structure interaction analysis of eccentricity and leaflet rigidity on thrombosis biomarkers in bioprosthetic aortic valve replacements

2022 ◽  
Author(s):  
David Oks ◽  
Mariano Vazquez ◽  
Guillaume Houzeaux ◽  
Constantine Butakoff ◽  
Cristobal Samaniego
Keyword(s):  
Aortic Valve ◽  
Computational Model ◽  
High Performance ◽  
Interaction Analysis ◽  
Thrombus Formation ◽  
Fluid Structure Interaction ◽  
Simulation Software ◽  
Fluid Structure ◽  
Structure Interaction

This work introduces the first 2-way fluid-structure interaction (FSI) computational model to study the effect of aortic annulus eccentricity on the performance and thrombogenic risk of cardiac bioprostheses. The model predicts that increasing eccentricities yield lower geometric orifice areas (GOAs) and higher normalized transvalvular pressure gradients (TPGs) for healthy cardiac outputs during systole, agreeing with in vitro experiments. Regions with peak values of residence time and shear rate are observed to grow with eccentricity in the sinus of Valsalva, indicating an elevated risk of thrombus formation for eccentric configurations. In addition, the computational model is used to analyze the effect of varying leaflet rigidity on both performance, thrombogenic and calcification risks with applications to tissue-engineered prostheses, observing an increase in systolic and diastolic TPGs, and decrease in systolic GOA, which translates to decreased valve performance for more rigid leaflets. An increased thrombogenic risk is detected for the most rigid valves. Peak solid stresses are also analyzed, and observed to increase with rigidity, elevating risk of valve calcification and structural failure. The immersed FSI method was implemented in a high-performance computing multi-physics simulation software, and validated against a well known FSI benchmark. The aortic valve bioprosthesis model is qualitatively contrasted against experimental data, showing good agreement in closed and open states. To the authors' knowledge this is the first computational FSI model to study the effect of eccentricity or leaflet rigidity on thrombogenic biomarkers, providing a novel tool to aid device manufacturers and clinical practitioners.

scholarly journals Effects of Sulcus Vocalis Depth on Phonation in Three-Dimensional Fluid-Structure Interaction Laryngeal Models

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Changwei Zhou ◽  
Lili Zhang ◽  
Yuanbo Wu ◽  
Xiaojun Zhang ◽  
Di Wu ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Vocal Folds ◽  
Threshold Pressure ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Phonation Threshold Pressure ◽  
Different Types ◽  
Sulcus Vocalis

Sulcus vocalis is an indentation parallel to the edge of vocal fold, which may extend into the cover and ligament layer of the vocal fold or deeper. The effects of sulcus vocalis depth d on phonation and the vocal cord vibrations are investigated in this study. The three-dimensional laryngeal models were established for healthy vocal folds (0 mm) and different types of sulcus vocalis with the typical depth of 1 mm, 2 mm, and 3 mm. These models with fluid-structure interaction (FSI) are computed numerically by sequential coupling method, which includes an immersed boundary method (IBM) for modelling the glottal airflow, a finite-element method (FEM) for modelling vocal fold tissue. The results show that a deeper sulcus vocalis in the cover layer decreases the vibrating frequency of vocal folds and expands the prephonatory glottal half-width which increases the phonation threshold pressure. The larger sulcus vocalis depth makes vocal folds difficult to vibrate and phonate. The effects of sulcus vocalis depth suggest that the feature such as phonation threshold pressure could assist in the detection of healthy vocal folds and different types of sulcus vocalis.

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