scholarly journals Suppression mechanism study of attached apex drogue on undesirable inflation phenomena

2018 ◽  
Vol 69 (02) ◽  
pp. 128-132
Author(s):  
LI JUN ◽  
CHENG HAN ◽  
YANG JING
Keyword(s):  
Interaction Model ◽  
Computational Domain ◽  
Analysis Model ◽  
Mechanism Study ◽  
Deformation Method ◽  
Explicit Finite Element ◽  
Suppression Effect ◽  
Contact Algorithm ◽  
Structure Interaction ◽  
Suppression Mechanism

At present, the studies of suppression effect of attached apex drogue on undesirable inflation were seriously dependent on experiments. The experiments were difficult to reveal the suppression mechanism due to the difficulty of data collection. In this paper, a FSI (Fluid Structure Interaction) model based on explicit finite element method was proposed to study the suppression mechanism. The graphical deformation method was used to realize the movement of computational domain. At the same time, the velocity conditions were applied on the boundaries of computational domain, which was used to simulate the external wind field. The coupling between the fluid and structure described by Lagrangian meshes was realized by contact algorithm. Finally, an extra-large parachute was taken as the research object, and the suppression mechanism of attached apex drogue was analyzed according to the numerical results. The effect of different attached apex drogues with different resistance characteristics also was analyzed by the above FSI model. The analysis model and method proposed in this paper could provide the design basis of extra-large parachute.

Wind-Structure Interaction by the Numerical Simulation

1999 ◽  
Vol 15 (1) ◽  
pp. 35-39
Author(s):  
D. L. Young ◽  
J. T. Chang
Keyword(s):  
External Field ◽  
Moving Boundary ◽  
Stokes Equations ◽  
Numerical Code ◽  
Computational Domain ◽  
Arbitrary Lagrangian Eulerian ◽  
Number Range ◽  
Explicit Finite Element ◽  
Structure Interaction ◽  
Wind Structure

ABSTRACTA new computational procedure is developed to solve the external field problems of the incompressible viscous flows. The method is able to solve the infinite boundary value problems by extracting the boundary effects coming from the finite computational domain. The present method is based on the projection method of the Navier-Stokes equations. We use three-step explicit finite element method to solve the momentum equation of the flow motion. The external field solver of the boundary element is used to treat the pressure Poisson equation. The arbitrary Lagrangian-Eulerian method is employed to deal with the moving boundary, such as wind-structure interaction problems. For illustration of the present numerical code, a vortex-induced cross-flow oscillations of a circular cylinder mounted on an elastic dashpot-spring system is considered. The phenomena of the beat, lock-in, and resonance are revealed in the Reynolds number range between 100 and 110, which are much narrower than the previous studies.

scholarly journals CFD Investigation of Trout-Like Configuration Holding Station near an Obstruction

Fluids ◽  
2021 ◽  
Vol 6 (6) ◽  
pp. 204
Author(s):  
Kamran Fouladi ◽  
David J. Coughlin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Laboratory Experiment ◽  
Numerical Models ◽  
Interaction Model ◽  
Underwater Vehicle ◽  
Water Stream ◽  
Hydrodynamic Analysis ◽  
Structure Interaction ◽  
Vehicle Systems

This report presents the development of a fluid-structure interaction model using commercial Computational fluid dynamics software and in-house developed User Defined Function to simulate the motion of a trout Department of Mechanical Engineering, Widener University holding station in a moving water stream. The oscillation model used in this study is based on the observations of trout swimming in a respirometry tank in a laboratory experiment. The numerical simulations showed results that are consistent with laboratory observations of a trout holding station in the tank without obstruction and trout entrained to the side of the cylindrical obstruction. This paper will be helpful in the development of numerical models for the hydrodynamic analysis of bioinspired unmanned underwater vehicle systems.

scholarly journals A new method of phase-shifting and displacement of unit motor to suppress the thrust fluctuation of linear motor

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110087
Author(s):  
Feng Zhou ◽  
Han Zhao ◽  
Xiaoke Liu ◽  
Fujia Wang
Keyword(s):  
Permanent Magnet ◽  
Linear Motor ◽  
Phase Shifting ◽  
New Method ◽  
Analysis Model ◽  
End Effects ◽  
Element Analysis ◽  
Suppression Effect ◽  
Permanent Magnet Linear Motor ◽  
Thrust Fluctuation

Permanent magnet linear motors can cause thrust fluctuation due to cogging and end effects, which will affect the operation stability of the linear motor. In order to solve this problem, a new method of eliminating alveolar force by using phase-shifting and displacement is proposed in this paper. Taking the cylindrical permanent magnet linear motor as an example, the traditional cylindrical permanent magnet linear motor is divided into two unit-motors, and established finite element analysis model of cylindrical permanent magnet linear motor. It is different from other traditional methods, the thrust fluctuation was reduced by both phase-shifting and displacement simultaneously in this paper, and through simulation analysis, it is determined that the thrust fluctuation suppression effect was the best when the cogging distance was shifted by half. Furthermore, a comparative simulation was made on whether the magnetic insulating material was used. The simulation results show that: The method proposed in this paper can effectively suppress the thrust fluctuation of the cylindrical permanent magnet linear motor. And it can be applied to other similar motor designs. Compared with the traditional method of suppressing thrust fluctuation, the mechanical structure and the technological process of suppressing thrust fluctuation used in this method are simpler.

scholarly journals Linear Stability Analysis and Validation of a Unified Solution Method for Fluid-Structure-Interaction on Structural Dynamic Problems

2005 ◽  
Author(s):  
C. G. Giannopapa ◽  
G. Papadakis
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Solution Method ◽  
Fluid Structure Interaction ◽  
Analytic Solutions ◽  
Computational Domain ◽  
Structural Dynamic ◽  
Fluid Structure ◽  
Structure Interaction

In the conventional approach for fluid-structure interaction problems, the fluid and solid components are treated separately and information is exchanged across their interface. According to the conventional terminology, the current numerical methods can be grouped in two major categories: Partitioned methods and monolithic methods. Both methods use two separate sets of equations for fluid and solid. A unified solution method has been presented [1], which is different from these methods. The new method treats both fluid and solid as a single continuum, thus the whole computational domain is treated as one entity discretised on a single grid. Its behavior is described by a single set of equations, which are solved fully implicitly. In this paper, 2 time marching and one spatial discretisation scheme, widely used for fluids’ equations, are applied for the solution of the equations for solids. Using linear stability analysis, the accuracy and dissipation characteristics of the resulting difference equations are examined. The aforementioned schemes are applied to a transient structural problem (beam bending) and the results compare favorably with available analytic solutions and are consistent with the conclusions of the stability analysis. A parametric investigation using different meshes, time steps and beam sizes is also presented. For all cases examined the numerical solution was stable and robust and proved to be suitable for the next stage of application to full fluid-structure interaction problems.

Seismic Response Analysis of Soil-Structure Interaction on Base Isolation Structure

2013 ◽  
Vol 663 ◽  
pp. 87-91
Author(s):  
Ying Bo Pang
Keyword(s):  
Finite Element ◽  
Seismic Response ◽  
Soil Structure ◽  
Base Isolation ◽  
Soil Structure Interaction ◽  
Response Analysis ◽  
Analysis Model ◽  
Seismic Response Analysis ◽  
Structure Interaction ◽  
Calculation Results

As an effective way of passive damping, isolation technology has been widely used in all types of building structures. Currently, for its theoretical analysis, it usually follows the rigid foundation assumption and ignores soil-structure interaction, which results in calculation results distortion in conducting seismic response analysis. In this paper, three-dimensional finite element method is used to establish finite element analysis model of large chassis single-tower base isolation structure which considers and do not consider soil-structure interaction. The calculation results show that: after considering soil-structure interaction, the dynamic characteristics of the isolation structure, and seismic response are subject to varying degrees of impact.

Fluid-Structure Interaction Simulation of the Edge-to-Edge Repair of the Mitral Valve in Functional and Degenerative States

2012 ◽  
Author(s):  
K. D. Lau ◽  
G. Burriesci ◽  
V. Díaz-Zuccarini
Keyword(s):  
Mitral Valve ◽  
Fluid Structure Interaction ◽  
Mitral Valve Regurgitation ◽  
Fluid Structure ◽  
Explicit Finite Element ◽  
Structure Interaction ◽  
Modelling Techniques ◽  
Induced Stresses ◽  
Annular Dilation ◽  
Ventricular Filling

The most common dysfunction of the mitral valve (MV) is mitral valve regurgitation (MVR) which accounts for approximately 70% of native MV dysfunction [1]. During closure, abnormal amounts of retrograde flow enter the left atrium altering ventricular haemodynamics, an issue which can lead to cardiac related pathologies. MVR is caused by a variety of different mechanisms which are either degenerative (myxomatous degeneration) or functional (annular dilation or papillary muscle displacement) [2]. Correction of MVR is performed by repairing existing valve anatomy or replacement with a prosthetic substitute, however repair is preferred as mortality rates are reduced (2.0% against 6.1% for replacement) along with other valve related complications [3]. A common and popular method of repair is the edge-to-edge repair (ETER), which aims to correct MVR by surgically connecting the regurgitant region through reducing the inter-leaflet distance. Although MV function is improved in systole, induced stresses are significantly increased in diastole where the MV is typically in a low state of stress. In order to assess the effect of this technique in diastole, where the dynamics of both the MV and ventricular filling are disrupted it is required to use fluid-structure interaction (FSI) modelling techniques. Here a FSI model of the of the MV has been described, using this model the resulting induced stresses from the ETER in both functional and degenerative states of the MV have been simulated and assessed using the explicit finite element code LS-DYNA.

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