Characterization of the Sharkskin Defect and its Development with the Flow Conditions**

1989 ◽  
Vol 4 (2) ◽  
pp. 78-84 ◽  
Author(s):  
P. Beaufils ◽  
B. Vergnes ◽  
J. F. Agassant
Keyword(s):  
Flow Conditions

scholarly journals ECOSYSTEM BIOMASS AS A KEY PARAMETER DETERMINING ITS COASTAL PROTECTION SERVICE

2020 ◽  
pp. 29
Author(s):  
Maria Maza ◽  
Fernando Lopez-Arias ◽  
Javier L. Lara ◽  
Inigo J. Losada
Keyword(s):  
Leaf Traits ◽  
Biomechanical Properties ◽  
Coastal Protection ◽  
Flow Conditions ◽  
Flow Energy ◽  
Standing Biomass ◽  
Attenuation Relationships ◽  
Number Of Individuals ◽  
Key Parameter

Estimation of the flow energy dissipation induced by an ecosystem that accounts for its characteristics (i.e. biomechanical properties, morphology, density) and the incident hydrodynamic conditions is crucial if ecosystem-based coastal protection measurements want to be implemented. Characterization of a vegetated ecosystem by measuring leaf traits, biomechanical properties of plants and the number of individuals per unit area involves a lot of effort and is case-specific. Standing biomass can be a unique variable defining the flow energy attenuation capacity of the ecosystem. To explore its relation to the induced energy attenuation on the flow, a new set of experiments using real vegetation with contrasting morphology and biomechanical properties, and subjected to different incident flow conditions is presented. The obtained standing biomass-attenuation relationships will help to quantify the expected coastal protection provided by different vegetated ecosystems based on their standing biomass and the flow conditions.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/-qaKkBWZApk

Validation of a Fluid-Structure Interaction Model for the Characterization of Transcatheter Mitral Valve Repair Devices

2021 ◽  
Vol 7 (2) ◽  
pp. 605-608
Author(s):  
Robert Ott ◽  
Alper Ö Öner ◽  
Paul Hermann Bellé ◽  
Finja Borowski ◽  
Klaus-Peter Schmitz ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Flow Conditions ◽  
Valve Repair ◽  
Structure Interaction ◽  
Device Implantation ◽  
Transcatheter Mitral Valve Repair ◽  
Vitro Data ◽  
In Vitro Data

Abstract Mitral regurgitation (MR) is the second most frequent indication for heart valve surgery and catheter interventions. According to European and US-American guidelines, transcatheter mitral valve repair in general and transcatheter edge-to-edge repair (TEER) in particular may be considered as a treatment option for selected high-risk patients. However, the biomechanical impact of TEERdevices on the mitral valve (MV) has not yet been fully understood. To address this problem, a 3D-Fluid-Structure Interaction (FSI) framework utilizing non-linear Finite Element Analysis (FEA) for the MV apparatus and Smoothed Particle Hydrodynamics (SPH) for the pulsatile fluid flow was developed and validated against in vitro data. An artificial MV-model (MVM) with a prolapse in the A2-P2 region and a custom-made TEER device implanted in the A2-P2 region were used for the in vitro investigations. In accordance with ISO 5910, projected mitral orifice areas (PMOA), flow rates as well as atrial and ventricular pressures were measured under pulsatile flow conditions before and after TEER device implantation. For the FSI-model, the MVM geometry was reconstructed by means of microcomputed tomography in a quasi-stress-free configuration. Quasi-static tensile test data was utilized for the development of linear- and hyperelastic material models of the chordae tendineae and leaflets, respectively. The fluid flow was modelled assuming an incompressible, homogenous Newtonian behaviour. Time-varying in vitro transmitral pressure loading was applied as a boundary condition. In vitro investigations show that TEER device implantation in the A2-P2 region effectively reduces the regurgitation fraction (RF) from 55 % to 13 %. Moreover, the comparison of experimental and numerical data yields a deviation of 2.09 % for the RF and a deviation of 0.40 % and 6.47 % for the maximum and minimum PMOA, respectively. The developed FSI-framework is in good agreement with in vitro data and is therefore applicable for the characterization of the biomechanical impact of different TEER devices under pulsatile flow conditions.

scholarly journals Gas permeability in rarefied flow conditions for characterization of mineral membrane support

2020 ◽  
Vol 79 ◽  
pp. 44-53 ◽  
Author(s):  
C. Savaro ◽  
J.P. Bonnet ◽  
M.V. Johansson ◽  
P. Perrier ◽  
I. Graur ◽  
...  
Keyword(s):  
Gas Permeability ◽  
Flow Conditions ◽  
Rarefied Flow

scholarly journals Characterization of bedload discharge in bores and very unsteady flows in an ephemeral channel

2018 ◽  
Vol 40 ◽  
pp. 02036 ◽  
Author(s):  
Eran Halfi ◽  
Vishal Deshpande ◽  
Joel P. L. Johnson ◽  
David Katoshevski ◽  
Ian Reid ◽  
...  
Keyword(s):  
High Frequency ◽  
Global Climate ◽  
Unsteady Flows ◽  
Bedload Transport ◽  
Flow Conditions ◽  
Safety Issues ◽  
Frequency Monitoring ◽  
Event Occurrence

Bedload flux under steady flow conditions is calculated by a multitude of available methods and equations. Yet, very little is known about the effect of very unsteady flows, such as flash floods and specifically bores, on bedload flux. The unpredictable nature of the floods together with many logistic difficulties and safety issues in monitoring explain this gap in knowledge. Global climate change may increase flood event occurrence, making their understanding even more crucial. The methodology of our study is based on automatically monitoring bedload flux (Reid slot samplers). Automation allowed high frequency monitoring of hydraulic parameters and bedload flux. Added novelty includes pipe and plate microphones for capturing acoustic signals of bedload sediments and 3-D velocimetry for characterizing turbulence. Alerting sensors and cellular data transmission enabled onsite presence upon bore arrival. Calibration between the acoustic indirect sensors and the direct slot samplers allows determination of bedload flux at a frequency of 1 Hz. Analyses of flood events indicate an increase in turbulent kinetic energy, instantaneous vertical velocities, shear stress and bedload flux during the rising limb within the first two minutes after bore arrival. This has implications for the likely destabilization of the channel bed and for bedload transport after passage of the bore and during subsequent, less unsteady flows.

Investigations on the characterization of laminar and transitional flow conditions after high pressure homogenization orifices

2014 ◽  
Vol 18 (4) ◽  
pp. 599-612 ◽  
Author(s):  
Katharina Kelemen ◽  
F. E. Crowther ◽  
C. Cierpka ◽  
L. L. Hecht ◽  
C. J. Kähler ◽  
...  
Keyword(s):  
High Pressure ◽  
Transitional Flow ◽  
High Pressure Homogenization ◽  
Flow Conditions

Characterization of a centrifugal pump impeller under two-phase flow conditions

2008 ◽  
Vol 63 (1-4) ◽  
pp. 18-22 ◽  
Author(s):  
Jose Caridad ◽  
Miguel Asuaje ◽  
Frank Kenyery ◽  
Andrés Tremante ◽  
Orlando Aguillón
Keyword(s):  
Centrifugal Pump ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
Pump Impeller ◽  
Centrifugal Pump Impeller
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