A Perturbation Method for Low-Frequency Fluid-Structure Interaction Problems

1973 ◽  
Vol 40 (2) ◽  
pp. 388-394 ◽  
Author(s):  
Y. K. Lou
Keyword(s):  
Wave Equation ◽  
Perturbation Method ◽  
Electromagnetic Scattering ◽  
Perturbation Methods ◽  
Separation Of Variables ◽  
Fluid Structure Interaction ◽  
Low Frequency ◽  
Approximate Solutions ◽  
Fluid Structure ◽  
Structure Interaction

Perturbation methods have been used for electromagnetic scattering and diffraction problems in recent years. A similar method suitable for low-frequency fluid-structure interaction problems is presented. The essence of the method lies in the fact that approximate solutions for fluid-structure interaction problems can be obtained from a set of Poisson’s equations, rather than from the reduced wave equation. The method is particularly useful for those problems where the Poisson’s equation may be solved by the method of separation of variables while the reduced wave equation cannot. As an illustrative example, the vibrations of a submerged spherical shell is studied using the perturbation method and the accuracy of the method is demonstrated.

Low Frequency Piezoelectric Synthetic Jets

2010 ◽  
Author(s):  
Charles E. Seeley ◽  
Mehmet Arik ◽  
Yogen Uttukar ◽  
Tunc Icoz
Keyword(s):  
Low Cost ◽  
Heated Surface ◽  
Fluid Structure Interaction ◽  
Low Frequency ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Active Cooling ◽  
Compact Size

Active cooling is often required for circuit boards with high heat generation densities. Synthetic jets driven with piezoelectric actuators offer interesting capabilities for localized active cooling of electronics due to their compact size, low cost and substantial cooling effectiveness. The design of synthetic jets for specific applications requires practical design tools that capture the strong fluid structure interaction without long run times. There is particular interest in synthetic jets that have a low operating frequency to reduce noise levels. This paper describes how common finite element (FE) and computational fluid dynamics (CFD) codes can be used to calculate parameters for a synthetic jet fluid structure interaction (FSI) model that only requires a limited number of degrees of freedom and is solved using a direct approach for low frequency synthetic jets. Tests are performed based on impinging on a heated surface to measure heat transfer enhancement. The test results are compared to the FSI model results for validation and agreement is found to be good in the frequency range of interest from 200 to 500 Hz.

Modal Analysis of a Nuclear Reactor With Fluid-Structure Interaction: Influence of Fluid Compressibility

2006 ◽  
Author(s):  
Jean-Franc¸ois Sigrist ◽  
Daniel Broc
Keyword(s):  
Modal Analysis ◽  
Compressible Fluid ◽  
Nuclear Reactor ◽  
Fluid Structure Interaction ◽  
Low Frequency ◽  
Operating Pressure ◽  
Fluid Structure ◽  
Displacement Potential ◽  
Structure Interaction ◽  
Temperature Conditions

The present paper deals with the modal analysis of a nuclear with fluid-structure interaction effects. In a previous study, added mass and added stiffness effects due to fluid-structure interaction were modeled and studied. A dynamic analysis was performed for a seismic excitation, i.e. in the low frequency range. The present study deals with high frequency analysis, i.e. taking into account compressibility effects in the fluid problem. Elasto-acoustic coupling phenomena are studied and described in the industrial case. The elasto-acoustic coupled problem is formulated using the displacement/pressure-displacement potential coupled formulation which yields symmetric matrices. A modal analysis is first performed on the fluid problem alone, with a calculation of acoustic eigenfrequencies and the corresponding modal masses. A modal analysis is then performed for the coupled fluid-structure problem in the case of an incompressible fluid and a compressible fluid at standard pressure and temperature conditions and for a compressible fluid at the operating pressure and temperature conditions. Elasto-coupling effects are then highlighted and discussed.

scholarly journals Experimental Characterization of High-Amplitude Fluid–Structure Interaction of a Flexible Hydrofoil at High Reynolds Number

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Brian R. Elbing ◽  
Steven D. Young ◽  
Michael L. Jonson ◽  
Robert L. Campbell ◽  
Brent A. Craven ◽  
...  
Keyword(s):  
Initial Conditions ◽  
Model Development ◽  
Fluid Structure Interaction ◽  
Low Frequency ◽  
High Amplitude ◽  
Cylinder Wake ◽  
Constraint Forces ◽  
Fluid Structure ◽  
Structure Interaction ◽  
High Reynolds

Abstract A fluid–structure interaction (FSI) experiment was performed to study low-frequency (∼10 Hz), high-amplitude (±3.5% of the span) fin motion. This was achieved by placing an Inconel swept-fin at −9.6 deg angle-of-attack within the wake of a roughened cylinder. Speeds between 2.5 and 3.6 m/s produced cylinder diameter-based Reynolds numbers between 190,000 and 280,000, respectively. Detailed descriptions of the geometry, material/structural behavior, fluid properties, and initial conditions are provided to facilitate computational model development. Given the initial conditions, the resulting forced fin behavior was characterized with measurements of the mean and fluctuating velocity upstream of the fin (i.e., within the cylinder wake), fin tip/surface motion, and fin constraint forces/moments. This work provides a detailed experimental dataset of conditions mimicking a crashback event that is also a challenging FSI benchmark problem involving turbulent, vortex-induced structure motion. It has been used as a validation condition for FSI simulations, and it can be used to validate other FSI models as well as identifying strengths and weaknesses of various modeling approaches.

Fluid-Structure Interaction Model for Low-Frequency Synthetic Jets

AIAA Journal ◽  
2011 ◽  
Vol 49 (2) ◽  
pp. 316-323 ◽  
Author(s):  
Charles E. Seeley ◽  
Yogen Utturkar ◽  
Mehmet Arik ◽  
Tunc Icoz
Keyword(s):  
Fluid Structure Interaction ◽  
Low Frequency ◽  
Interaction Model ◽  
Synthetic Jets ◽  
Fluid Structure ◽  
Structure Interaction
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