Study of the sneezing effects on the real human upper airway using fluid–structure interaction method

Author(s):  
Hamidreza Mortazavy Beni ◽  
Kamran Hassani ◽  
Siamak Khorramymehr
2014 ◽  
Vol 553 ◽  
pp. 275-280 ◽  
Author(s):  
Mo Yin Zhao ◽  
Tracie J. Barber ◽  
Peter A. Cistulli ◽  
Kate Sutherland ◽  
Gary Rosengarten

Obstructive Sleep Apnea (OSA) is a common sleep disorder characterized by repetitive collapse of the upper airway (UA) during sleep. Treatment options for OSA include mandibular advancement splints (MAS), worn intra-orally to protrude the lower jaw to stabilize the airway. However not all patients will respond to MAS therapy and individual effects on the upper airway are not well understood. Simulations of airway behavior represent a non-invasive means to understand this disorder and treatment responses in individual patients. The aims of this study was to perform analysis of upper airway (UA) occlusion and flow dynamics in OSA using the fluid structure interaction (FSI) method, and secondly to observe changes associated with MAS usage. Magnetic resonance imaging (MRI) scans were obtained with and without mandibular advance splint (MAS) treatment in a patient known to be a treatment responder. Computational models of the anatomically correct UA geometry were reconstructed for both pre-and post-treatment (MAS) conditions. By comparing the simulation results, the treatment success of MAS was demonstrated by smaller UA structure deformation (maximum 2mm) post-treatment relative to the pre-treatment fully collapsed (maximum 6mm) counterpart. The UA collapse was located at the oropharynx and the low oropharyngeal pressure (-51 Pa to-39 Pa) was induced by the velopharyngeal jet flow (maximum 10 m/s). The results support previous OSA computational fluid dynamics (CFD) studies by indicating similar UA pressure drop and maximum velocity values. These findings lay a firm platform for the application of computational models for the study of the biomechanical properties of the upper airway in the pathogenesis and treatment of OSA.


2019 ◽  
Vol 11 (3) ◽  
pp. 168781401982858
Author(s):  
Liaojun Zhang ◽  
Shuo Wang ◽  
Guojiang Yin ◽  
Chaonian Guan

Current studies on the operation of the axial pump mainly focus on hydraulic performances, while the coupled interaction between the fluid and structure attracts little attention. This study aims to provide numerical investigation into the vibration features in a vertical axial pump based on two-way iterative fluid–structure interaction method. Three-dimensional coupling model was established with high-quality structured grids of ADINA software. Turbulent flow features were studied under design condition, using shear–stress transport k-ω turbulence model and sliding mesh approach. Typical measure points along and perpendicular to flow direction in fluid domain were selected to analyze pressure pulsation features of the impeller and fixed guide vane. By contrast, vibration features of equivalent stress in corresponding structural positions were investigated and compared based on fluid–structure interaction method. In order to explore fluid–structure interaction vibration mechanism, distribution of main frequencies and amplitudes of the measure points was presented based on the Fast Fourier Transformation method. The results reveal the time and frequency law of fluid pressure pulsation and structural vibration at the same position in the vertical axial pump while additionally provide important theoretical guidance for optimization design and safe operation of the vertical axial pump.


2019 ◽  
Vol 91 ◽  
pp. 102734 ◽  
Author(s):  
Weipao Miao ◽  
Chun Li ◽  
Yuanbo Wang ◽  
Bin Xiang ◽  
Qingsong Liu ◽  
...  

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