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.

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.

scholarly journals Fluid Structure Interaction Modelling of Tidal Turbine Performance and Structural Loads in a Velocity Shear Environment

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1837 ◽  
Author(s):  
Mujahid Badshah ◽  
Saeed Badshah ◽  
Kushsairy Kadir
Keyword(s):  
Fluid Dynamic ◽  
Turbine Blades ◽  
Fluid Structure Interaction ◽  
Angular Position ◽  
Uniform Flow ◽  
Velocity Shear ◽  
Power Coefficient ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Stress And Deformation

Tidal Current Turbine (TCT) blades are highly flexible and undergo considerable deflection due to fluid interactions. Unlike Computational Fluid Dynamic (CFD) models Fluid Structure Interaction (FSI) models are able to model this hydroelastic behavior. In this work a coupled modular FSI approach was adopted to develop an FSI model for the performance evaluation and structural load characterization of a TCT under uniform and profiled flow. Results indicate that for a uniform flow case the FSI model predicted the turbine power coefficient CP with an error of 4.8% when compared with experimental data. For the rigid blade Reynolds Averaged Navier Stokes (RANS) CFD model this error was 9.8%. The turbine blades were subjected to uniform stress and deformation during the rotation of the turbine in a uniform flow. However, for a profiled flow the stress and deformation at the turbine blades varied with the angular position of turbine blade, resulting in a 22.1% variation in stress during a rotation cycle. This variation in stress is quite significant and can have serious implications for the fatigue life of turbine blades.

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.

scholarly journals Stochastic fluid structure interaction of three-dimensional plates facing a uniform flow

2016 ◽  
Vol 794 ◽  
Author(s):  
O. Cadot
Keyword(s):  
Fluid Structure Interaction ◽  
Angular Position ◽  
Three Dimensional ◽  
Uniform Flow ◽  
Steady States ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Fluid Forces ◽  
Long Time ◽  
Order Of Magnitude

An experiment on a flat rectangular plate facing a uniform flow at $Re=264\,000$ shows the importance of the base pressure loading on the asymmetric static modes of the turbulent wake. The plate is free to rotate around its short symmetry axis. For plates with aspect ratio ${\it\kappa}<6$, the angular position exhibits strong random discontinuities between steady states of non-zero angles. The steady states have long time durations, more than one order of magnitude greater than the convective time scale. The discontinuities, comparable to rare and violent events, are due to strong fluid forces associated with a drastic global change of the three-dimensional wake – mainly the switching between the static asymmetric modes. A clear transition occurs at ${\it\kappa}=6$, for which the angular fluctuations are minimum, leading for ${\it\kappa}>6$ to a classical fluid structure interaction with periodic fluctuations. The transition is supported by a recent global stability analysis of rectangular fixed plates in the laminar regime.

A Parametric Modeling Approach for Prediction of Load Distribution due to Fluid Structure Interaction on Aircraft Structures

2019 ◽  
Author(s):  
Ahmet Barutcu ◽  
Recep M. Gorguluarslan
Keyword(s):  
Load Distribution ◽  
Fluid Structure Interaction ◽  
Parametric Modeling ◽  
Generation Process ◽  
Aircraft Wing ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Bézier Surface ◽  
Modeling Approach ◽  
Bezier Surface

Abstract The Fluid Structure Interaction (FSI) is a critical multi-physics phenomenon in the aerospace applications for computing loads. Including the FSI effects on the analysis requires high computational cost. A computationally efficient framework is presented in this study for predicting the FSI effects. The high-fidelity structural model is reduced on the elastic axis by using an efficient structural idealization technique. A parametric model generation process is developed by using Bezier surface control vertices (CVs) to estimate the changing load distribution under deformation. The aircraft wing outer surface is created by using Bezier surface modeling method for this purpose. The CVs of the surfaces are perturbed to predict the effect of the deformed shape on the load distribution. This method allows to predict the load distribution by using a few CVs instead of using all grid points. The Aerodynamic Influence Coefficients (AIC) matrix is generated based on the predicted loads based on this parametric modeling approach instead of conducting computationally expensive fluid flow analysis. The presented framework is implemented for an aircraft wing design to show its efficacy.

High Fidelity Simulation of Fluid-Structure Interaction in a 1½ Stage Axial Turbine

2019 ◽  
Author(s):  
Joshua Zorn ◽  
Roger Davis ◽  
John Clark
Keyword(s):  
Control Volume ◽  
Numerical Technique ◽  
Fluid Structure Interaction ◽  
Momentum Conservation ◽  
Second Order ◽  
Constitutive Relationship ◽  
High Fidelity ◽  
Time Step ◽  
Fluid Structure ◽  
Structure Interaction

Abstract A high fidelity, fully coupled numerical technique for the simulation of airfoil and turbomachinery aeroelasticity configurations is presented. The unsteady structural and fluid dynamics equations are discretized by a control volume technique which is second order accurate in space along with a dual time-step scheme that is second order accurate in time. The momentum conservation equation for the solid is written in terms of the Piola-Kirchoff stresses and the displacement velocity components. The stress tensor is related to the Lagrangian strain and displacement tensors using the St. Venant-Kirchoff constitutive relationship. Source terms at the surface of the solid are included to account for surface pressure and body forces. Previous fluid-structure interaction studies of Turek’s cylinder flag and the AGARD 445.6 airfoil have provided confidence needed to accurately perform fluid structure interaction simulations in turbomachinery. In this study, a 1½ stage axial transonic turbine is simulated and results are validated with experimental data. Simulation results indicate that the inclusion of airfoil vibration leads to improved agreement with experimental unsteady surface pressures compared to simulations with fixed airfoils.

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