The present paper focuses on the fluid-structure interaction of flexible marine propellers. The aim is to develop a simulation method to predict the hydro-elastic performance. To compare with the experimental results,...
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ISBN:
(纸本)9783037855072
The present paper focuses on the fluid-structure interaction of flexible marine propellers. The aim is to develop a simulation method to predict the hydro-elastic performance. To compare with the experimental results, the geometry of propeller DTMB4119 is used. The solution procedure first computes the hydrodynamic pressures due to rigid-blade rotation via the BEM (Boundary Element Methods, BEM). The hydrodynamic pressures are then applied as external normal surface traction for the FEM (Finite Element Methods, FEM) solid model to obtain the deformed geometry. The commercial FEM code is then used to solve the equation of motion in the rotating blade-fixed coordinate system. Iterations are implemented between BEM and FEM solvers until the solution converges. This study shows that the simulation method developed in this paper is reasonable.
According to Hamilton's principle and conservation law of mass and momentum, governing equations of fluid-structure interaction and structural dynamics of a flexible riser transporting high-speed spiral flow are d...
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ISBN:
(纸本)9780791886892
According to Hamilton's principle and conservation law of mass and momentum, governing equations of fluid-structure interaction and structural dynamics of a flexible riser transporting high-speed spiral flow are developed for vortex-induced vibration (VIV) analysis for lifting pipe system in deep-sea mining. The bi-directional fluid-solid interaction between flexible riser and internal and external flows is achieved by data mapping and exchange among the flow field domain and the solid domain. where the radial basis function method is used for moving interpolation of the flow field grid boundaries and internal nodes. The governing equations are then discretized and solved by the finite element method. Based on the computational fluid dynamics (CFD) method, a three-dimensional flexible riser fluid-structure coupling numerical model is established, and the numerical accuracy of the model is verified. Furthermore, dynamic characteristics of VIV of the flexible riser transporting spiral flow are investigated and the effects of internal flow velocity of the spiral flow on VIV responses are evaluated. The results show that the variation of modal vibration pattern of the flexible riser under the combined excitation of internal and external flows is evident, and the flow velocity of internal flow have significant nonlinear effects on the inherent frequency and vibration deformation of the flexible riser.
The model of wind turbine was created by CATIA software, and then the simulation for blades and wind field was conducted by ANSYS software. The phenomena, such as tip vortex of blade, center vortex, and spiral trailin...
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ISBN:
(纸本)9783038352914
The model of wind turbine was created by CATIA software, and then the simulation for blades and wind field was conducted by ANSYS software. The phenomena, such as tip vortex of blade, center vortex, and spiral trailing edge vortex caused by the rotating wind turbine, were presented explicitly and the pressure distribution of wind field was obtained. This paper provides some guiding significance to the arrangement of wind turbine and the studies about loading, deformation, and stress of blades.
In the present work we study the spider's hair flow-sensing system by using fluid-structure interaction (FSI) numerical simulations. We observe experimentally the morphology of Theraphosa stirmi's hairs and ch...
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In the present work we study the spider's hair flow-sensing system by using fluid-structure interaction (FSI) numerical simulations. We observe experimentally the morphology of Theraphosa stirmi's hairs and characterize their mechanical properties through nanotensile tests. We then use the obtained information as input for the computational model. We study the effect of a varying air velocity and a varying hair spacing on the mechanical stresses and displacements. Our results can be of interest for the design of novel bio-inspired systems and structures for smart sensors and robotics. (C) 2018 Elsevier Ltd. All rights reserved.
Viscous fluid-structure interaction is treated with an arbitrary Lagrangian- Eulerian formulation. The spatial discretization is performed by the spectral element method for the fluid part where the Navier-Stokes equa...
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Viscous fluid-structure interaction is treated with an arbitrary Lagrangian- Eulerian formulation. The spatial discretization is performed by the spectral element method for the fluid part where the Navier-Stokes equations are integrated and in the solid part where transient linear elasticity is described by the Navier equations. Time marching algorithms are second-order accurate in time in both the fluid and the solid. The algorithm is applied to the flow in a plane channel partially obstructed by a solid component able to move under the action of the fluid flow.
We address two difficult points in the simulation of blood flows in compliant vessels: the fluid and structure meshes generation and the solution of the fluid-structure problem with large displacements. The proposed s...
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We address two difficult points in the simulation of blood flows in compliant vessels: the fluid and structure meshes generation and the solution of the fluid-structure problem with large displacements. The proposed strategy allows to perform realistic simulations on geometries coming from medical imaging. (C) 2004 Elsevier Ltd. All rights reserved.
Dynamic response of two concentric horizontal composite cylinders containing water in the annulus was investigated under impact loading so as to examine the load transfer from the outer cylinder to the inner through a...
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Dynamic response of two concentric horizontal composite cylinders containing water in the annulus was investigated under impact loading so as to examine the load transfer from the outer cylinder to the inner through a fluid medium. Different water filling levels in the annulus were considered along with different magnitudes of impact loading. Both of the composite cylinders were 254 mm long, had a diameter of 76.2 mm and 88.9 mm, respectively, and were assembled concentrically. Both experimental and numerical studies were conducted to supplement each other. The experimental set-up was designed and constructed. Both cylinders were constrained at both ends, and the water level was varied in the annulus of the two cylinders. The experimental set-up used strain gages at certain locations. For each experiment, the strain data were collected and examined. Then, the fast Fourier transform was applied to the strain data to identify major vibrational frequencies and to examine the effect of the added mass. The numerical study provided additional results which were not measured by the experiment, such as the fluid pressure in the annulus and the dynamic motion of the cylinders. The fluid-structure interaction resulted in significant coupling of the outer and inner composite cylinders.
The class of fluid-structure interaction models in the physical dimension d = 2,3 has been the object of intense mathematical studies in the past several years. In the case of static interface, justified to be appropr...
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The class of fluid-structure interaction models in the physical dimension d = 2,3 has been the object of intense mathematical studies in the past several years. In the case of static interface, justified to be appropriate for small, rapid oscillations of the structure, the typical configuration considers a structure – modeled by a d-dimensional wave-type equation –surrounded by a fluid –modeled by the d-dimensional dynamic Stokes equation involving pressure. Coupling takes place at the common interface of the two media where the individual equations evolve and is given by differential operators. Thus, the overall system provides a physical illustration of hyperbolic- parabolic coupling. The present dissertation represents a key distinctive novelty over past literature whereby the structure equation includes a (strong) Kelvin-Voigt damping. Two specific cases of structure are analyzed, both with physically significant interface conditions: (1) a wave with Kelvin-Voigt damping (d = 2, 3), and (2) a plate with Kelvin-Voigt damping (d = 2). In both cases, this dissertation provides the following main results: (i) analyticity of the s.c. contraction semigroup (on a natural physical space), describing the overall coupled dynamics; (ii) a detailed (and surprising) spectral analysis of its generator; (iii) uniform stability of such semigroup, either on the entire space or, when this is not true, on a natural subspace of codimension one, obtained by factoring out the one dimensional eigenspace corresponding to the zero eigenvalue. The final chapter includes the original work done during a summer 2021 NSF-MSGI Internship at the Oak Ridge National Laboratory, under the sponsorship of senior scientist Dr. J. Nutaro. It introduces a novel quantized state integration method that is analogous to the explicit, second order Runge-Kutta technique. For a single differential equation over an interval where the solution is monotonic, such method exhibits an error proportional to the squ
Nuclear reactors pump coolant through their core and heat exchangers at massive mass flow rates to sustain energy production. These demanding requirements push engineers to extreme levels of optimization to safely sus...
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Nuclear reactors pump coolant through their core and heat exchangers at massive mass flow rates to sustain energy production. These demanding requirements push engineers to extreme levels of optimization to safely sustain the transfer of energy. High flow rates introduce the possibility of flow-induced vibrations. Reactor core and heat-exchanger/steam generator designs go through many stages of experimentation to ensure that problematic flow-induced vibrations do not arise. Advances in computational capabilities introduce the possibility of creating predictive simulations that accelerate the iterative design process and replace expensive physical experiments. Simulation methods for fluid-structure interactions are rapidly developing and undergoing extensive verification and validation. Computational fluid dynamics code Nek5000 and computational structural mechanics code Diablo have been coupled to create a highly scalable, high-fidelity fluid-structure interaction code. A fully coupled model of crossflow through a tube bundle has been simulated using the Nek5000-Diablo code for validation purposes. Simulations at three velocities were performed to test the method’s capabilities of capturing the onset of large amplitude vibrations that occur at a critical velocity for the tube bundle. The simulation results compared favorably to the experiment on which it was based and gave further insight into the mechanisms behindthe vibrations. A 7-pin bundle of wire-wrapped fuel pins was simulated using Nek5000 and the forces exerted on the pins captured. A scheme was developed to synthesize force histories of indefinite length replicating the Nek5000 force signals, forming a modifiedone-directional coupling procedure. Multiple structure simulations were performed, observing the effects of pin-to-pin, and pin-to shroud contact scenarios on the resulting vibrations. The shroud was found to effectively limit vibrations to short wave-lengths onthe order of 1/6th helical pitch even w
To study the structure-borne noise of shock absorber caused by the opening of the compensation valve against the spring force acting on the compensation valve and the adhesion force between the compensation valve and ...
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ISBN:
(纸本)9781450365703
To study the structure-borne noise of shock absorber caused by the opening of the compensation valve against the spring force acting on the compensation valve and the adhesion force between the compensation valve and its seat, a fluid-structure interaction method is adopted to analyze the generation mechanism at the beginning of the extension stroke. A mathematical model is established for the shock absorber. A three-dimensional finite element model is developed by ADINA and the leader-follower method is introduced to control the mesh distortion. The displacement curve of the compensation valve is computed. The flow field distribution and characteristics are obtained before and after the opening of the compensation valve.
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