Nanoscale Fluid-Structure Interactions in Cytoplasm During Freezing

2012 ◽  
Author(s):  
Altug Ozcelikkale ◽  
Bumsoo Han
Keyword(s):  
Theoretical Model ◽  
Physical Properties ◽  
Spatial Heterogeneity ◽  
Fluid Structure Interaction ◽  
Fluid Structure Interactions ◽  
Spatial Homogeneity ◽  
Intracellular Space ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Poroelastic Material

In this study, a theoretical model is developed to simulate the biophysical events in the intracellular spaces considering the biphasic, i.e., poroelastic, behavior of the cytoplasm. Most previous studies in the cryobiology literature have modeled the biophysical response of cells to freezing assuming the spatial homogeneity of all physical properties within the intracellular space without considering fluid-structure interaction in both the intracellular and extracellular spaces. However, a few recent studies strongly indicate that spatial heterogeneity in the intracellular space occurs during freezing. We thus model the cytoplasm as a poroelastic material considering nanoscale fluid-structure interaction between the cytoskeleton and cytosol, and the effects of hierarchical fluid-structure interaction across the cell during freezing.

Analysis of Fluid-Structure Interaction of an Elastic Blade in Cascade

2002 ◽  
Author(s):  
R. C. K. Leung ◽  
Y. L. Lau ◽  
R. M. C. Si
Keyword(s):  
Numerical Technique ◽  
Fluid Structure Interaction ◽  
Uniform Flow ◽  
Frequency Parameter ◽  
Generation Process ◽  
Noise Generation ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Normalized Frequency

A time-marching numerical model for the analysis of fluid-structure interaction caused by oncoming alternating vortices has been developed by Jadic et al. (1998). Its applicability to analyzing realistic fluid–structure interaction problems has successfully been established in a recent experimental work of a flat plate in a circular cylinder wake (Lau et al. 2002). Using the model, So et al. (1999) have predicted that, under the excitation of oncoming Karman vortex street (KVS) vortices, an elastic airfoil/blade in inviscid uniform flow exhibits two types of fluid–structure resonance, namely aerodynamic and structural resonance. Aerodynamic resonance is of pure aerodynamic origin and occurs with rigid airfoil/blade excited at normalized frequency parameter c/d = 0.5, 1.5, 2.5 etc., where c is the blade chord and d is the streamwise separation between two neighboring vortices. For an elastic airfoil/blade, as a result of coupled fluid–structure interaction, structural resonance occurs at a normalized frequency close to the natural frequency in vacuo of the airfoil/blade. The occurrence of fluid-structure resonance has also been shown critical in noise generation process (Leung & So 2001). The present study extends the scope of the analysis to fluid–structure interactions occurring in axial–flow turbomachine cascade. When the flow is passing through the rotor, it generates wakes containing KVS vortices behind the rotor blades. The convecting wake will induce perturbations on the downstream stator blades at a wake passing frequency (Rao 1991). Such wake–blade interaction is important in determining the fatigue life of the blades and noise generation of the cascade. The cascade analysis starts with modeling the two-dimensional turbine stator by five high–loading blades evenly separated by s in inviscid uniform flow. Oncoming KVS vortices are released upstream to represent the passing wake originating from the rotor, and are allowed to pass through the stator blades. The blade pitch to blade chord ratio s/c and normalized frequency parameter c/d are important parameters of the problems. Fluid–structure interactions are fully resolved by the same numerical technique (Jadic et al. 1998, So et al. 1999). The combined effects of s/c and c/d on the aerodynamic and structural responses of the central blade are studied and discussed.

Fluid Structure Interactions for Blast Wave Mitigation

2011 ◽  
Vol 78 (3) ◽  
Author(s):  
Wen Peng ◽  
Zhaoyan Zhang ◽  
George Gogos ◽  
George Gazonas
Keyword(s):  
Shock Wave ◽  
Blast Wave ◽  
Fluid Structure Interaction ◽  
Wave Formation ◽  
Plate Motion ◽  
Fluid Structure Interactions ◽  
Free Standing ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Shock Wave Formation

The dynamic response of a free-standing plate subjected to a blast wave is studied numerically to investigate the effects of fluid-structure interaction (FSI) in blast wave mitigation. Previous work on the FSI between a blast wave and a free-standing plate (Kambouchev, N., et al., 2006, “Nonlinear Compressibility Effects in Fluid-Structure Interaction and Their Implications on the Air-Blast Loading of Structures,” J. Appl. Phys., 100(6), p. 063519) has assumed a constant atmospheric pressure at the back of the plate and neglected the resistance caused by the shock wave formation due to the receding motion of the plate. This paper develops an FSI model that includes the resistance caused by the shock wave formation at the back of the plate. The numerical results show that the resistance to the plate motion is especially pronounced for a light plate, and as a result, the previous work overpredicts the mitigation effects of FSI. Therefore, the effects of the interaction between the plate and the shock wave formation at the back of the plate should be considered in blast wave mitigation.

Cerebrospinal Fluid-Structure Interactions: The Development of Mathematical Models Accessible to Clinicians

2014 ◽  
Author(s):  
Novak S. J. Elliott
Keyword(s):  
Cerebrospinal Fluid ◽  
Mathematical Models ◽  
Clinical Application ◽  
Fluid Structure Interaction ◽  
Pressure Vessels ◽  
Fluid Structure Interactions ◽  
Research Methodologies ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Perceived Complexity

Physical scientists work with clinicians on biomechanical problems, yet the predictive capabilities of mathematical models often remain elusive to clinical collaborators. This is due to both conceptual differences in the research methodologies of each discipline, and the perceived complexity of even simple models. This limits expert medical input, affecting the applicability of the results. Moreover, a lack of understanding undermines the medical practitioner’s confidence in modeling predictions, hampering its clinical application. In this paper we consider the disease syringomyelia, which involves the fluid-structure interaction of pressure vessels and pipes, as a paradigm of the nexus between the modeling approaches of physical scientists and clinicians. The observations made are broadly applicable to cross-disciplinary research between engineers and non-technical specialists, such as may occur in academic-industrial collaborations.

scholarly journals Wave Propagation Across Solid-Fluid Interface With Fluid-Structure Interaction

2015 ◽  
Author(s):  
Tomohisa Kojima ◽  
Kazuaki Inaba ◽  
Kosuke Takahashi
Keyword(s):  
Wave Propagation ◽  
Theoretical Model ◽  
Characteristic Impedance ◽  
Fluid Structure Interaction ◽  
Fluid Interface ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Mechanism Of Wave Propagation ◽  
Free Falling ◽  
The Impact

This paper reports on investigations conducted with a view towards developing a theoretical model for wave propagation across solid-fluid interfaces with fluid-structure interaction. Although many studies have been conducted, the mechanism of wave propagation close to the solid-fluid interface remains unclear. Consequently, our aim is to clarify the mechanism of wave propagation across the solid-fluid interface with fluid-structure interaction and develop a theoretical model to explain this phenomenon. In experiments conducted to develop the theory, a free-falling steel projectile is used to impact the top of a solid buffer placed immediately above the surface of water within a polycarbonate tube. The stress waves created as a result of the impact of the projectile propagated through the buffer and reached the interface of the buffer and water (fluid) in the tube. Two different buffers (polycarbonate and aluminum) were used to examine the interaction effects. The results of the experiments indicated that the amplitude of the interface pressure increased in accordance with the characteristic impedance of the solid medium. This cannot be explained by the classical theory of wave reflection and transmission. Thus, it is clear that on the solid-fluid interface with fluid-structure interaction, classical theories alone cannot precisely predict the generated pressure.

scholarly journals Numerical Methods for Fluid-Structure Interaction — A Review

2012 ◽  
Vol 12 (2) ◽  
pp. 337-377 ◽  
Author(s):  
Gene Hou ◽  
Jin Wang ◽  
Anita Layton
Keyword(s):  
Numerical Methods ◽  
Fluid Structure Interaction ◽  
Fluid Flows ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Wide Range ◽  
Recent Developments ◽  
Conforming Meshes ◽  
Incompressible Fluid Flows

AbstractThe interactions between incompressible fluid flows and immersed structures are nonlinear multi-physics phenomena that have applications to a wide range of scientific and engineering disciplines. In this article, we review representative numerical methods based on conforming and non-conforming meshes that are currently available for computing fluid-structure interaction problems, with an emphasis on some of the recent developments in the field. A goal is to categorize the selected methods and assess their accuracy and efficiency. We discuss challenges faced by researchers in this field, and we emphasize the importance of interdisciplinary effort for advancing the study in fluid-structure interactions.

Dynamics of Wave Propagation Across Solid–Fluid Movable Interface in Fluid–Structure Interaction

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Tomohisa Kojima ◽  
Kazuaki Inaba ◽  
Kosuke Takahashi ◽  
Farid Triawan ◽  
Kikuo Kishimoto
Keyword(s):  
Wave Propagation ◽  
Theoretical Model ◽  
Fluid Structure Interaction ◽  
Momentum Conservation ◽  
Local Deformation ◽  
Fluid Interfaces ◽  
Interface Pressure ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Mechanism Of Wave Propagation

A theoretical model for wave propagation across solid–fluid interfaces with fluid–structure interaction (FSI) was explored by conducting experiments. Although many studies have been conducted on solid–solid and fluid–fluid interfaces, the mechanism of wave propagation across solid–fluid interfaces has not been well examined. Consequently, our aim is to clarify the mechanism of wave propagation across a solid–fluid interface with the movement of the interface and develop a theoretical model to explain this phenomenon. In the experiments conducted, a free-falling steel projectile was used to impact a solid buffer placed immediately above the surface of water within a polycarbonate (PC) tube. Two different buffers (aluminum and polycarbonate) were used to examine the relation between wave propagation across the interface of the buffer and water and the interface movement. With the experimental results, we confirmed that the peak value of the interface pressure can be predicted via acoustic theory based on the assumption that projectile and buffer behave as an elastic body with local deformation by wave propagation. On the other hand, it was revealed that the average profile of the interface pressure can be predicted with the momentum conservation between the projectile and the buffer assumed to be rigid and momentum increase of fluid. The momentum transmitted to the fluid gradually increases as the wave propagates and causes a gradual decrease in the interface pressure. The amount of momentum was estimated via the wave speed in the fluid-filled tube by taking into account the coupling of the fluid and the tube.

Simulation of Fluid-Structure Interaction of Crossflow Through a Tube Bundle and Experimental Validation

2017 ◽  
Author(s):  
Landon Brockmeyer ◽  
Jerome Solberg ◽  
Elia Merzari ◽  
Yassin Hassan
Keyword(s):  
Solid Mechanics ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Spectral Element ◽  
Fluid Structure Interactions ◽  
Low Velocity ◽  
Simulation Code ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Flow Induced Vibrations

Fluid-structure interactions are complex, multi-physics phenomena of consequence for many fluid-flow domains. Modern multi-physics codes are becoming capable of simulating with great accuracy the interaction between fluid and structure dynamics. While fluid-structure interactions can occur in many forms, flow-induced vibrations are of particular interest. Such vibrations can result in the fatigue and even failure of a vibrating geometry. The prediction and minimization of flow induced vibrations are of particular importance for heat exchangers, which commonly contain bundles of tubes experiencing high-velocity crossflow. The present study simulates the fluid-structure interaction for flexibly mounted tube bundles undergoing crossflow and compares the results with experiment. The simulation code consists of a spectral-element fluid solver directly coupled with a finite-element solid mechanics solver. The fluid solver locally adapts the fluid mesh to accommodate the moving solids. In order to minimize computational expense, low Reynolds number flows are considered, allowing for a thin, pseudo 2-D domain. The flow remains laminar for the majority of the domain, with local areas of turbulence. The pins are connected to springs that supply a restorative force equivalent to the flexible mounts of the corresponding experiment. Fluid-only simulations are performed for flow spanning low to moderate velocities and compared visually with experimental flow visualizations. Coupled fluid-structure interactions are simulated with low velocity and vibration amplitudes. The measured vibration amplitudes of the simulation agree well with those of the experiment.

Validation of Computational Fluid Structure Interaction Models for Shape Optimization Under Blast Impact

2010 ◽  
Author(s):  
Huade Tan ◽  
John Goetz ◽  
Andre´s Tovar ◽  
John E. Renaud
Keyword(s):  
Optimization Problems ◽  
Fluid Structure Interaction ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Blast Energy ◽  
Interaction Simulation ◽  
Fully Coupled ◽  
Structural Optimization Problem ◽  
Interaction Problem

A first order structural optimization problem is examined to evaluate the effects of structural geometry on blast energy transfer in a fully coupled fluid structure interaction problem. The fidelity of the fluid structure interaction simulation is shown to yield significant insights into the blast mitigation problem not captured in similar empirically based blast models. An emphasis is placed on the accuracy of simulating such fluid structure interactions and its implications on designing continuum level structures. Higher order design methodologies and algorithms are discussed for the application of such fully coupled simulations on vehicle level optimization problems.

Sign in / Sign up

Export Citation Format

Share Document