Research on Effect Factors of Mechanical Response of Cross-Fault Buried Gas Pipeline Based on Fluid-Structure Interaction

2021 ◽  
Author(s):  
Qiaochu Li ◽  
Sha He
Keyword(s):  
Mechanical Response ◽  
Fluid Structure Interaction ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Optimal Angle ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Pass Through ◽  
Buried Gas Pipeline ◽  
Reversed Fault

Abstract Long-distance buried pipelines inescapably go through seismic fracture zones which makes the buried pipelines be easily influenced by the diastrophism. Most of the existing studies only focus on the two-phase contact between pipeline and soil, and the mechanical behavior of the cross-fault pipeline under transportation condition has not been studied. In this paper, ADINA finite element software was used to establish a pipe-soil-fluid three-phase coupling model based on fluid-structure interaction (FSI), and the effect factors of mechanical response of cross-fault buried gas pipeline were studied. Results indicate the following conclusions: (1) The model considering the effect of fluid-structure interaction can effectively simulate the mechanical response of pipelines in the actual working condition. (2) It is safer for the pipeline to pass through the strike-slip fault, and the most dangerous to pass through the reversed fault. (3) When the fault displacement is less than 1.3m, the optimal angle range to pass through the strike-slip fault is 30° to 60°, otherwise the optimal angle range is 30° to 45°; the optimal angle range to pass through the normal fault is 30° to 60°; the optimal angle to pass through the reversed fault is 90°. (4) When passing through the reversed fault, the optimal buried depth of pipeline is 1m-1.5m. (5) When the fault displacement is less than 1.3m, a certain delivery pressure (8MPa) can enhance the ability of pipeline to resist the strike-slip fault dislocation.

scholarly journals Toward the Virtual Benchmarking of Pneumatic Ventricular Assist Devices: Application of a Novel Fluid–Structure Interaction-Based Strategy to the Penn State 12 cc Device

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Alessandro Caimi ◽  
Francesco Sturla ◽  
Bryan Good ◽  
Marco Vidotto ◽  
Rachele De Ponti ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Fluid Structure Interaction ◽  
Ventricular Assist Devices ◽  
Uniaxial Tensile ◽  
Ventricular Assist ◽  
Fluid Structure ◽  
Assist Devices ◽  
Structure Interaction ◽  
Penn State ◽  
Blood Chamber

The pediatric use of pneumatic ventricular assist devices (VADs) as a bridge to heart transplant still suffers for short-term major complications such as bleeding and thromboembolism. Although numerical techniques are increasingly exploited to support the process of device optimization, an effective virtual benchmark is still lacking. Focusing on the 12 cc Penn State pneumatic VAD, we developed a novel fluid–structure interaction (FSI) model able to capture the device functioning, reproducing the mechanical interplay between the diaphragm, the blood chamber, and the pneumatic actuation. The FSI model included the diaphragm mechanical response from uniaxial tensile tests, realistic VAD pressure operative conditions from a dedicated mock loop system, and the behavior of VAD valves. Our FSI-based benchmark effectively captured the complexity of the diaphragm dynamics. During diastole, the initial slow diaphragm retraction in the air chamber was followed by a more rapid phase; asymmetries were noticed in the diaphragm configuration during its systolic inflation in the blood chamber. The FSI model also captured the major features of the device fluid dynamics. In particular, during diastole, a rotational wall washing pattern is promoted by the penetrating inlet jet with a low-velocity region located in the center of the device. Our numerical analysis of the 12 cc Penn State VAD points out the potential of the proposed FSI approach well resembling previous experimental evidences; if further tested and validated, it could be exploited as a virtual benchmark to deepen VAD-related complications and to support the ongoing optimization of pediatric devices.

scholarly journals Cavitation Effects on Fluid Structure Interaction in the Case of a 2D Hydrofoil

2005 ◽  
Author(s):  
Philippe Ausoni ◽  
Mohamed Farhat ◽  
Franc¸ois Avellan ◽  
Xavier Escaler ◽  
Eduard Egusquiza
Keyword(s):  
High Speed ◽  
Mechanical Response ◽  
Fluid Structure Interaction ◽  
Torsional Mode ◽  
Fluid Structure ◽  
Generation Frequency ◽  
Structure Interaction ◽  
2D Structure ◽  
Lock In ◽  
Advection Velocity

In the present study, we have carried out an experimental investigation on the fluid-structure interaction caused by Karman vortices in the wake of a truncated 2D hydrofoil. The instrumentation involves a high frequency accelerometer and high speed visualisation. The mechanical response of the hydrofoil to the hydrodynamic excitation is monitored with the help of a portable digital vibrometer. Moreover, a specific optical device is developed to investigate the dynamic of the cavitating wake. The survey of the generation frequency of the Karman vortices with respect to the flow velocity reveals a Strouhal behaviour and three resonances of the hydrofoil. Out of hydro-elastic coupling conditions, the observation of the vortex structures reveals a strong 3D pattern despite the fact that the hydrofoil is 2D. The maximum fluid-structure interaction occurs for the torsional mode where lock-in is observed for upstream velocities ranging from 11 to 13 m/s. In this case, the vortices exhibit a 2D structure. The cavitation occurrence within the core of Karman vortices leads to a significant increase of their generation frequency. We have observed that hydrofoil resonance may be whether avoided or triggered by cavitation development. The study of the Karman vortices dynamic reveals that their advection velocity increases (4%) with the development of the wake cavitation meanwhile their streamwise spacing decreases.

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