Fluid-structure Interaction Analysis Research Articles

Application of a Coupled Eulerian-Lagrangian Approach to the Shape and Force of Scientific Balloons

Scientific balloons provide an inexpensive and reliable platform for near-space scientific experiments. The analysis of the balloon geometry and forces has always been a major concern for balloon designers. Most previous studies have focused solely on the fully inflated shapes and forces of balloons, analyzing only the membrane structure and simplifying the effects of internal and external gases into a gradient pressure difference. This approach lacks consideration of the fluid–structure interaction (FSI) of scientific balloons. This paper utilizes the Coupled Eulerian–Lagrangian (CEL) method in the Abaqus/Explicit simulation environment to analyze the FSI effects of scientific balloons under the influence of internal helium and external air. Three typical working conditions of scientific balloons are selected for simulation analysis. First, a three-dimensional spherical balloon is simulated during the ascent process to verify the correctness of the CEL simulation framework. This also demonstrates the membrane folding characteristics during balloon ascent, which could not be calculated in previous two-dimensional axisymmetric simulations. Next, the study explores balloon shapes that deviate from quasi-static pressure distributions due to the motion of internal helium. These include the “mushroom” shape observed during the dynamic launching of the balloon on the ground and the “sail” shape caused by lateral airflow. The mushroom shape arises from the sudden loss of the bottom constraint, causing the internal helium to move upward while being resisted by the air at the balloon’s top. The simulation successfully replicates the rapid waist transition and the downward concavity at the top due to air resistance, while also providing the corresponding force distribution. For the sail-shaped condition, the simulation analyzes the balloon’s tilt angle and the characteristic upturn of its windward surface. By a comparison with no-wind conditions, this study quantifies the impact of wind on the forces acting on the balloon, offering practical guidance for balloon launching. The CEL simulation framework established in this study not only provides a new tool for the FSI analysis of scientific balloons but also enriches the mechanical analysis results of these balloons.

Numerical Simulation of Fluid-Structure Interaction in Axillary Artery Venoarterial Extracorporeal Membrane Oxygenation for Heart Failure Patients.

Although axillary artery venoarterial extracorporeal membrane oxygenation (VA-ECMO) has been utilized as a mechanical circulatory support for patients with end-stage heart failure (HF), there is currently insufficient evidence to support its effectiveness and safety. The objective of this study was to analyze the hemodynamic effects of axillary artery VA-ECMO. To this end, we obtained CT angiographic imaging data of the aorta from a carefully selected heart failure patient with a cardiac output of 2.1 L/min. These data were used to construct a detailed fluid-structure interaction model of the aorta. Axillary artery VA-ECMO was then simulated within this model, maintaining a constant flow rate of 3 L/min. The intra-aortic balloon counterpulsation (IABP) balloon was simulated to inflate and deflate in synchrony with the diastolic and systolic phases of the cardiac cycle. Hemodynamic effects, including left ventricular (LV) pressure afterload, vessel wall stress, perfusion of vital organs, blood flow pulsatility, and the watershed region, were calculated using fluid-structure interaction analysis. We found that axillary artery VA-ECMO delivers well-distributed, oxygen-rich blood flow but may increase left ventricular (LV) afterload and reduce cerebral blood flow. However, when combined with IABP, it unloads LV pressure and increases cerebral blood flow. Integrating axillary artery VA-ECMO with IABP can promote cardiac function recovery and improve oxygen-rich blood perfusion to the vital organs of heart failure patients.

Analysis of the two-way fluid-structure interaction between the rice canopy and the downwash airflow of a quadcopter UAV

Analysis of the two-way fluid-structure interaction between the rice canopy and the downwash airflow of a quadcopter UAV

Fluid-structure interaction analysis of blood flow in collapsible channels: Implications for sports performance

Fluid-structure interaction analysis of blood flow in collapsible channels: Implications for sports performance

Fluid–Structure Interaction Analysis and Experimental Study for the Structural Safety of Hydrogen Refueling Nozzle

Fluid–Structure Interaction Analysis and Experimental Study for the Structural Safety of Hydrogen Refueling Nozzle

Fluid structure Interaction analysis for rupture risk assessment in patients with middle cerebral artery aneurysms

Accurate rupture risk assessment is essential for optimizing treatment decisions in patients with cerebral aneurysms. While computational fluid dynamics (CFD) has provided critical insights into aneurysmal hemodynamics, most analyses focus on blood flow patterns, neglecting the biomechanical properties of the aneurysm wall. To address this limitation, we applied Fluid-Structure Interaction (FSI) analysis, an integrative approach that simulates the dynamic interplay between hemodynamics and wall mechanics, offering a more comprehensive risk assessment. In this study, we used advanced FSI techniques to investigate the rupture risk of middle cerebral artery bifurcation (MCA) aneurysms, analyzing a cohort of 125 patients treated for a MCA aneurysm at Kepler University Hospital, Linz, Austria. Multivariate analysis identified two significant rupture predictors: High Equivalent Stress Area (HESA; p = 0.049), which quantifies stress distribution relative to the aneurysm surface, and Gaussian curvature (GLN; p = 0.031), which captures geometric complexity. We also introduce the HGD index, a novel composite metric combining HESA, GLN, and Maximum Wall Displacement, designed to enhance predictive accuracy. With a threshold of 0.075, the HGD index exhibited excellent diagnostic performance; in internal validation, 24 of 25 ruptured aneurysms surpassed this threshold, yielding a sensitivity of 0.96. In a 5-fold cross validation the reliability of results was confirmed. Our findings demonstrate that the HGD index provides superior rupture risk stratification compared to conventional single-parameter models, offering a more robust tool for the assessment of complex aneurysmal structures. Further multicenter studies are warranted to refine and validate the HGD index, advancing its potential for clinical application and improving patient outcomes.

Wind-induced structural behavior and optical performance of a lightweight composite-based paraboloidal solar dish

Among the four available concentrating solar-thermal (CST) power systems, parabolic dish systems show great potential as the preferred technology for renewable electricity generation. Nonetheless, the weight of the support structure poses a major hurdle to its development. As of present, solar dishes utilize steel structures to hold the reflective panels which amount to a lot of weight, necessitating large and expensive drive units and increases energy consumption. Hence, for the dishes to advance and further become economically feasible in the near future, the structures found need to be replaced with cost-effective materials that not only diminish the weight but still maintain the structural integrity found with the steel. Hence, this investigation embodies the first effort in literature to explore the viability of utilizing honeycomb sandwich composites as a lightweight and robust support structure for solar dishes, with the ability to cope with the aerodynamic loads imposed upon them during operation. Through combined fluid-structure interaction (FSI) and ray tracing analysis, the wind-induced structural behavior and optical performance of the sandwich composite-based paraboloidal solar dish were investigated under various loading scenarios at various azimuth and elevation angles. Under dissimilar operational conditions, the proposed system exhibited varying behavior characteristics, with the worst conditions being assessed according to relevant material failure and optical standards. With the worst operational condition taking place at 0° azimuth and 30° elevation, the detailed FSI-ray tracing analysis demonstrated that the dish managed to satisfy the set specifications, highlighting the potential and effectiveness of using honeycomb sandwich composites as a support structure for parabolic dish systems.

Fluid–Structure Interaction Analysis of Brain Tissue During Head Impacts Using Newtonian and Non-Newtonian Cerebrospinal Fluid Models

Fluid–Structure Interaction Analysis of Brain Tissue During Head Impacts Using Newtonian and Non-Newtonian Cerebrospinal Fluid Models

Modeling Fibrous Tissue in Vascular Fluid-Structure Interaction: A Morphology-Based Pipeline and Biomechanical Significance.

Modeling fibrous tissue for vascular fluid-structure interaction analysis poses significant challenges due to the lack of effective tools for preparing simulation data from medical images. This limitation hinders the physiologically realistic modeling of vasculature and its use in clinical settings. Leveraging an established lumen modeling strategy, we propose a comprehensive pipeline for generating thick-walled artery models. A specialized mesh generation procedure is developed to ensure mesh continuity across the lumen and wall interface. Exploiting the centerline information, a series of procedures are introduced for generating local basis vectors within the arterial wall. The procedures are tailored to handle thick-walled tissues where basis vectors may exhibit transmural variations. Additionally, we propose methods for accurately identifying the centerline in multi-branched vessels and bifurcating regions. These modeling approaches are algorithmically implementable, rendering them readily integrable into mainstream cardiovascular modeling software. The developed fiber generation method is evaluated against the strategy using linear elastostatics analysis, demonstrating that the proposed approach yields satisfactory fiber definitions in the considered benchmark. Finally, we examine the impact of anisotropic arterial wall models on the vascular fluid-structure interaction analysis through numerical examples, employing the neo-Hookean model for comparative purposes. The first case involves an idealized curved geometry, while the second studies an image-based abdominal aorta model. Our numerical results reveal that the deformation and stress distribution are critically related to the constitutive model of the wall, whereas hemodynamic factors are less sensitive to the wall model. This work paves the way for more accurate image-based vascular modeling and enhances the prediction of arterial behavior under physiologically realistic conditions.

Influence of Atherosclerosis on Haemodynamics: A Comparison of Healthy and Stenosed Patient Specific Carotid Artery

Cardiovascular disease (CVD) is one major cause of morbidity caused by the progress of atherosclerosis without any symptoms and has a high risk of Transient Ischemic Stroke (TIS). The carotid bifurcation and bulb are the region where the blood flow is irregular, which may lead to the progression of the plague. The flow disruption due to stenosis in idealised carotid artery has been extensively investigated using Fluid Structure interaction (FSI). However, the haemodynamic of patient specific carotid artery has been intensively studied. In this study, a comparison of blood flow in healthy and stenosed (80% blockage in the carotid bulb region) was carried out using Two- way FSI analysis considering non-Newtonian blood viscosity and isotropic property for vessel wall. Haemodynamic parameters such as velocity streamline, pressure, vorticity, helicity, Time-Averaged Wall shear stress (TAWSS) and Oscillatory Shear Index (OSI) were analysed along with structural parameters such as wall displacement and von Mises stress. The comparison between healthy and stenosed arteries reveals that stenosis significantly increases the velocity magnitude due to the reduced flow area caused by plaque buildup. This narrowing also results in elevated pressure upstream of the stenosis. In both healthy and stenosed arteries, maximum deformation occurs near the bifurcation at the left and right lateral sections, with the highest von Mises Stress located near the internal wall of the flow divider. In stenosed arteries, the stress magnitude is six times higher than in healthy arteries, illustrating the profound effect stenosis has on haemodynamic. Overall, the analysis emphasizes how stenosis disrupts normal blood flow and alters bio-fluid dynamics in the carotid artery

Fluid-Structure Interaction Analysis of Trapezoidal and Arc-Shaped Membranes Mimicking the Organ of Corti.

In a previous study [H. Shintaku etal., Sensors and Actuators A: Physical 158 (2010): 183-192], an artificially developed auditory sensor device showed a frequency selectivity in the range from 6.6 to 19.8 kHz in air and from 1.4 to 4.9 kHz in liquid. Furthermore, the sensor succeeded in obtaining auditory brain-stem responses in deafened guinea pigs [T. Inaoka etal., Proceedings of the National Academy of Sciences of the United States of America 108 (2011): 18390-18395]. Since then, several research groups have developed piezoelectric auditory devices that have the capability of acoustic/electric conversion. However, the piezoelectric devices are required to be optimally designed with respect to the frequency range in liquids. In the present study, focusing on the trapezoidal shape of the piezoelectric membrane, the vibration characteristics are numerically and experimentally investigated. In the numerical analysis, solving a three-dimensional fluid-structure interaction problem, resonant frequencies of the trapezoidal membrane are evaluated. Herein, Young's modulus of the membrane, which is made of polyvinylidene difluoride and is different from that of bulk, is properly determined to reproduce the experimental results measured in air. Using the modified elastic modulus for the membrane, the vibration modes and resonant frequencies in liquid are in good agreement with experimental results. It is also found that the resonant characteristics of the artificial basilar membrane for guinea pigs are quantitatively reproduced, considering the fluid-structure interaction. The present numerical method predicts experimental results and is available to improve the frequency selectivity of the piezoelectric membranes for artificial cochlear devices.

Fluid–Structure Interaction Analysis of Tsunamis Generated by the Falling Impact of Rigid Objects

Fluid–Structure Interaction Analysis of Tsunamis Generated by the Falling Impact of Rigid Objects

More accurate representation of interaction at the fluid–structure interface with an improved smoothed field gradient method

Flexible structures are wind-sensitive with a significant fluid–structure interaction (FSI). The FSI analysis, however, often has poor numerical stability and low convergence efficiency due to drastic changes of the physical fields induced by computation errors in local regions of the fluid–structure interface. This paper aims at addressing these problems with the proposal of a new method to smooth the gradient of the pressure field at the fluid–structure interface for an efficient convergence in the FSI analysis. The smoothed gradient theory is modified by introducing weight coefficients. The field of fluid pressure in each smoothing domain with large numerical fluctuations at the interface is then gradient smoothed with the proposed method and the modified field is obtained from the linear Taylor series expansion. The convergence of fluid and structure solvers for the proposed method is ensured within the commercial software FLUENT and ANSYS adopted. The proposed method is validated with experimental results from the literature. It is also numerically validated with a thin plate in viscous flow with different site categories and average wind velocities through comparison of results from conventional methods. The proposed method is found valid and accurate in the FSI analysis. It is relatively independent of a wide range of parameters with satisfactory robustness and notable improvement in the convergence of the FSI analysis.

Fluid-structure interaction analysis of a novel water-lubricated bearing with particle-dynamic effect: Theory and experiment

Fluid-structure interaction analysis of a novel water-lubricated bearing with particle-dynamic effect: Theory and experiment

Numerical model and effect of site condition on the coupled dynamic characteristics of water storage tank of AP1000 shield building

AbstractSince the Fukushima nuclear incident in 2011, the focus on nuclear safety has intensified significantly, leading to heightened demands for nuclear power plant modeling to go beyond the mere dynamic analysis of soil–structure interaction (SSI) or fluid–structure interaction (FSI). In current engineering practice, FSI is typically described using simplified forms, such as loads or added mass. However, this approach lacks a comprehensive analytical framework that integrates refined FSI analysis with soil–structure interaction (SSI). This study analyzes the dynamic response of the nuclear island structural system using a fully coupled fluid–structure–soil interaction (FSSI) model. The effectiveness and validity of the model are verified through case comparisons. Simulations were conducted using the parameters of five different types of nuclear power engineering sites for both homogeneous and layered foundations. The results indicated that the hydrodynamic pressure response and acceleration amplification of layered foundations significantly exceeded those of homogeneous foundations, underscoring the importance of considering layered sites in the comprehensive complex modeling of nuclear power projects.

Fluid structure interaction analysis of a high aspect ratio aeroelastic wing considering geometric nonlinearity

Fluid structure interaction analysis of a high aspect ratio aeroelastic wing considering geometric nonlinearity

Fluid-structure interaction analysis on flow field and vibration characteristics of gas proportional valve

Gas proportional valve (GPV) is used as the gas regulator for fully premixed low nitrogen condensing boiler, with the pressure regulation and flow output capacity determined by the condition of the valve core. To investigate the reliability of GPV valve core in engineering applications, this paper establishes three-dimensional models of the flow and solid fields, employing a coupled calculation method known as the two-way fluid-structure interaction method to analyze the characteristics of the flow field and the stability of the valve core. The results indicate that with the valve core opening, the vortex structures gradually form on both sides of the upper diaphragm, and the vibration strength of the valve core gradually increases with the formations of the vortices. The valve core vibrates the most strongly in the outflow direction, and the upper diaphragm oscillates between −0.05 mm and 0.03 mm. When the valve core is first opened to its maximum height, there will be a 0.2 mm impact rebound, and then gradually stabilize at the maximum opening position of 8 mm. Maximum stress always occurs at the stem to diaphragms connections, especially in the initial opening stage, where the stress reaching 5.17 MPa but remaining within the allowable limit of 30 MPa. This study also compares the flow field excitation with the valve core's natural frequency, identifying potential valve core resonance. This work provides valuable guidance for the flow field characteristics and valve core safety prediction of pneumatic GPVs.

Impact of Geometric Attributes on Abdominal Aortic Aneurysm Rupture Risk: An InVivo FSI-Based Study.

Reported in this paper is a cutting-edge computational investigation into the influence of geometric characteristics on abdominal aortic aneurysm (AAA) rupture risk, beyond the traditional measure of maximum aneurysm diameter. A Comprehensive fluid-structure interaction (FSI) analysis was employed to assess risk factors in a range of patient scenarios, with the use of three-dimensional (3D) AAA models reconstructed from patient-specific aortic data and finite element method. Wall shear stress (WSS), and its derivatives such as time-averaged WSS (TAWSS), oscillatory shear index (OSI), relative residence time (RRT) and transverse WSS (transWSS) offer insights into the force dynamics acting on the AAA wall. Emphasis is placed on these WSS-based metrics and seven key geometric indices. By correlating these geometric discrepancies with biomechanical phenomena, this study highlights the novel and profound impact of geometry on risk prediction. This study demonstrates the necessity of a multidimensional assessment approach, future efforts should complement these findings with experimental validations for an applicable approach for clinical use.

Analysis of the influence of bottom flow holes in control rod guide tubes on flow field and control rod displacement

During the operation of pressurized water reactors, flow-induced vibration issues are commonly encountered, where control rod components vibrate due to the impact of coolant flow, leading to wear, thereby posing a threat to the safe operation of the reactor. This paper conducts a detailed numerical simulation of the flow field and force distribution inside a full-scale lower control rod guide tube based on the CFD method. The fluid–structure interaction analysis is performed to reveal the influence of cross-flow under various operating conditions on the vibration and displacement of control rods. The research subject consists of 24 control rods, one continuous guide section, and six control rod guide cards. The lower part of the guide tube has two flow holes on each surface, with one assumed to be a cross-flow inlet and the others as outlets. The results indicate that when considering the cross-flow effect at the flow holes, 90 % of the coolant flows out from other flow holes at the bottom of the guide tube, resulting in increased transverse velocity at the bottom and the presence of numerous vortices. The magnitude and location of the force exerted on the control rod by coolant impact are correlated. The control rod closest to the inlet of the flow hole experiences the greatest force, approximately 5.35 times the average at other positions. At a cross-flow velocity of 0.4 m/s and a low frequency of 10 Hz, the maximum displacement of the control rod is 0.3355 mm.

Spatiotemporal mode extraction for fluid–structure interaction using mode decomposition

A fluid–structure interaction (FSI) analysis model was developed based on the partitioned coupling approach. The study analyzed the fluid and structure behavior in a well-established validation case known as the Turek–Hron FSI benchmark test. This test involves strong, unsteady interaction between fluid flow and an elastic flap behind a rigid cylinder. Comparison of the elastic flap displacement frequencies and amplitudes from the present FSI model with reference data showed good agreement, validating the model. Dynamic mode decomposition (DMD) was employed to extract fundamental structures from the complex spatiotemporal data obtained from the FSI analysis. In addition, a mode–sensing technique based on a greedy algorithm was developed, and significant modes were extracted with elastic flap displacement as a feature. The crucial modes for the elastic flap displacement were the second bending modes at specific frequencies. However, these results differed significantly from the natural frequencies of the second bending modes obtained via eigenmode analysis. This discrepancy can be attributed to the close coupling between the fluid and structure, which alters elastic deformation behavior. The study demonstrates the potential for straightforward extraction of essential fluid–structure coupling using FSI-DMD.