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The following problem statement demonstrates the deformation of a solid structure in a channel due to a fluid flow over time. Here, the continuously deforming geometry is approached using the Mesh Deformation Method(Arbitrary Largrangian-Eularian Model). The fluid flow in the channel inlet is fully developed and has laminar characteristics and is defined by the Incompressible Navier-Stokes Equation. The fluid domain is solved over the freely moving mesh. The solid body in the channel is a continuously deforming structure that is solved for a non-linear elastic criteria to allow large deformations. We compute the velocity profile, pressure distribution, Mesh Displacement and MeshVelocity values to compare with the mean inlet velocity using COMSOL Multiphysics using the Fluids solver.
Baseline CAD Geometry.
The geometry depicts a rectangular fluid flow domain with a member that stands cantilevered and has solid, structural property.
Mesh model of the CAD geometry depicts unstructured, free triangular element meshing in the fluid flow domain. The sizing is set to Fine elements. Moving mesh is defined with the fluid domain as the deformable zone and the flow channel boundary as fixed.
The velocity magnitude profile depicts the formation of a local separation zone behind the structure forming a vortex. The magnitude is maximum above the structure because of the narrowing of the flow area.
Similarly there is a high pressure region on the left side of the structure that causes deformation of the member. This accumulation of pressure is released as the fluid flows past the structure.
The stress induced in the solid member during the deformation is as follows. The top region continues to remain free of stress due to the free hanging nature while the stress concentration occurs at the fixed end of the member.
The graph is plotted for 3 parameters with respect to time. The inlet velocity increases as it narrows down near the member and then sets at a constant value after it passes through the member, but a higher value than the initial inlet condition.
The Mesh displacement is seen to be around the same value after the deformation has occoured. The elastic property is responsible for the slight drop in the displacement value in the graph.
The mesh movement velocity is seen to fluctuate from a positive peak to a negative before setting into stationary. This is also attributed towards the small degree of resilience of the member due to elastic structural property.
For a better understanding the figure below depicts the motion of the mesh.
The picture depicts the animation of the velocity profile of the geometry.
It can be observed that there is a well defined vortex formation during the deformation of the member.
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