scholarly journals A Static Fluid-Structure Interaction Analysis System Based on the Navier-Stokes Equations for the Prediction of Aerodynamic Characteristics of Aircraft

Author(s):  
Lucia Sargentini ◽  
Benjamin Cariteau ◽  
Morena Angelucci

This paper is related to fluid-structure interaction analysis of sodium cooled fast reactors core (Na-FBR). Sudden liquid evacuation between assemblies could lead to overall core movements (flowering and compaction) causing variations of core reactivity. The comprehension of the structure behavior during the evacuation could improve the knowledge about some SCRAMs for negative reactivity occurred in PHÉNIX reactor and could contribute on the study of the dynamic behavior of a FBR core. An experimental facility (PISE-2c) is designed composed by a Poly-methyl methacrylate hexagonal rods (2D-plan similitude with PHÉNIX assembly) with a very thin gap between assemblies. Another experimental device (PISE-1a) is designed and composed by a single hexagonal rod for testing the dynamic characteristics. Different experiments are envisaged: free vibrations and oscillations during water injection. A phenomenological analysis is reported showing the flow behavior in the gap and the structure response. Also computational simulations are presented in this paper. An efficient numerical method is used to solve Navier-Stokes equations coupled with structure dynamic equation. The numerical method is verified by the comparison of analytic models and experiments.


2014 ◽  
Vol 660 ◽  
pp. 927-931 ◽  
Author(s):  
Nazri Huzaimi bin Zakaria ◽  
Mohd Zamani Ngali ◽  
Ahmad Rivai

Fluid-Structure Interaction engages with complex geometry especially in biomechanical problem. In order to solve critical case studies such as cardiovascular diseases, we need the structure to be flexible and interact with the surrounding fluids. Thus, to simulate such systems, we have to consider both fluid and structure two-way interactions. An extra attention is needed to develop FSI algorithm in biomechanic problem, namely the algorithm to solve the governing equations, the coupling between the fluid and structural parameter and finally the algorithm for solving the grid connectivity. In this article, we will review essential works that have been done in FSI for biomechanic. Works on Navier–Stokes equations as the basis of the fluid solver and the equation of motion together with the finite element methods for the structure solver are thoroughly discussed. Important issues on the interface between structure and fluid solvers, discretised via Arbitrary Lagrangian–Eulerian grid are also pointed out. The aim is to provide a crystal clear understanding on how to develop an efficient algorithm to solve biomechanical Fluid-Structure Interaction problems in a matrix based programming platform.


2021 ◽  
Vol 2118 (1) ◽  
pp. 012003
Author(s):  
H E Calderón ◽  
L M Rada ◽  
J S De Plaza

Abstract This research focuses on improving the hydraulic behavior of a traditionally design bottom rack intake, from variations in roughness parameters, free height, and the inclusion of chamfers, establishing a contribution to the contrast between classical physics and the physics that takes over the partial resolution of the Navier-Stokes equations. To make possible the structure in OpenFOAM, it is necessary to use the geometric tool Salome-Meca, as well as a meshing tool (snappyHexMesh), and the InterFOAM solver in the processing stage. In the same way, through the turbulence model (K-E) local effects are evidenced in the Fluid-Structure interaction, as well as the identification of events and the development of the phenomenon of vorticity. The results show the improvement presented in some areas of the structure from the stabilization of the water flow through of the fluid-structure interaction change, the modification of the geometry and roughness, minimizing the presence of vertical vortices, cavitation, and surrounding areas. This allows us to conclude that traditional hydraulic do not consider the real physical flow behavior within the structure and neither the subsequent phenomena that develop, establishing as a starting point the need to rethink the design of the bottom rack intakes.


Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 94 ◽  
Author(s):  
Cornel Marius Murea

A monolithic semi-implicit method is presented for three-dimensional simulation of fluid–structure interaction problems. The updated Lagrangian framework is used for the structure modeled by linear elasticity equation and, for the fluid governed by the Navier–Stokes equations, we employ the Arbitrary Lagrangian Eulerian method. We use a global mesh for the fluid–structure domain where the fluid–structure interface is an interior boundary. The continuity of velocity at the interface is automatically satisfied by using globally continuous finite element for the velocity in the fluid–structure mesh. The method is fast because we solve only a linear system at each time step. Three-dimensional numerical tests are presented.


Author(s):  
Jeremiah N. Mpagazehe ◽  
C. Fred Higgs

In many tribological applications, such as journal bearings and gears, a fluid film is used to accommodate velocity between moving surfaces. To model the behavior of this film and to predict its ability to carry load, the Reynolds equation is predominantly employed. As computational processing power continues to increase, computational fluid dynamics (CFD) is increasingly being employed to predict the fluid behavior in lubrication environments. Using CFD is advantageous in that it can provide a more general approximation to the Navier-Stokes equations than the Reynolds equation. Moreover, using CFD allows for the simulation of multiphase flows as could occur during bearing contamination and bearing exit conditions. Because the bearing surfaces move relative to each other as they obtain equilibrium with the fluid pressure, there is a need to incorporate the moving boundary into the CFD calculation, which is a non-trivial task. In this work, a fluid-structure interaction (FSI) technique is explored as an approach to model the dynamic coupling between the moving bearing surfaces and the lubricant. The benefits of using an FSI approach are discussed and the results of its implementation in a lubricated sliding contact model are presented.


2017 ◽  
Vol 9 (1) ◽  
pp. 19
Author(s):  
Buyung Junaidin

This paper describes numerical simulation o f flexible High Altitude Long Endurance Unmanned Aerial Vehicle (HALE UAV)wingusing two-way fluid structure interaction (FSI) method. The HALE wing is designed with high aspect ratio. This configuration intended to reduce the vehicle induced drag and reduces the lift-loss at wingtip which caused by wingtip vortex. But the structure of the wing itself becomes more elastic that be able to give large deformation when the aerodynamic loads applied. This deformation changes the aerodynamic loads distribution on the wing that gives a new deformation to the wing structure and vice versa. This interaction in a couple process called as fluid structure interaction (FSI). ANSYS 15.0 software was used to simulate fluid structure interaction on the wing. The unsteadiness and viscous flows at low speed are evaluated using the solution o f timedependent Reynolds Averaged Navier-Stokes (RANS) with SST k-rn turbulent model. In addition, multiblock structured grids are generated to provide more accurate viscous result and to anticipate negative volume o f the mesh which may occur due to the deformation o f the wing during simulation. Five different o f simulations are performed with variation o f material characteristics including Young’s modulus and Poisson’s ratio.The results are global aerodynamic characteristics at various material characteristics.


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