20_Fluid Structure Coupling

In this post, I will execute the "fluid structure coupling" example found in the RADIOSS guide.

The description in the guide is as follows.

 

Solshing inside a fuel tank by simulating the fluid structure coupling. The tank deformation is achieved by appling an impsed velocity on the left corners. Water and air inside the tank are modeled with the ALE formulation. The tank container is described using a Lagrangian formulation.

A numerical simulation of fluid-structure coupling is performed on sloshing inside a deformable fuel tank. This example used the ALE (Arbitrary Lagrangian Eulerian) formulation and the hydrodynamic bi-material law to model interaction between water, air and the tank container.

 

Model Description

A rectangular tank made of steel is partially filled with water, the remainder being supplemented by air. The initial distribution pressure is known and supposed homogeneous. The tank container dimensions are 460mm*300mm*10mm, with thickness being at 2mm.

deformation of the tank container is generated by an impulse made on the left corner of the tank for analyzing the fluid-structure coupling.

 

The steel container is modeled using the elasto-plastic model of Johnson-Cook law with the following parameters:

 

Material Properties

Density : 0.0078g/mm^3

Young's modulus : 210000 MPa

Possion's ratio : 0.29

Yield stress : 180 MPa

Hardening parameter : 450 MPa

Hardening exponent : 0.5

 

Material Parameters - Liquid

Reference density : 0.001 g/mm^3

Bulk modulus : 2089 N/mm^2

Initial mass fraction : 100%

Shear kinematic viscosity : 0.001 mm^2/ms

 

Material Parameters - Gas

Reference density : 1.22*10e-6 g/mm^3

Shear kinematic viscosity : 0.00143 mm^2/ms

Constant perfect gas : 1.4

Initial pressure reference gas : 0.1 N/mm^2

 

The main solid TYPE14 properties for air/water parts

Quadratic bulk viscosity/linear bulk viscosity : 10^-20

Hourglass bulk coefficient : 10^-5

 

Model Method

Air and water are modeled using the ALE formulation and the bi-material law. The tank container used a Lagrangian formulation and an elasto-plastic material law

 

Using the ALE formulation, the brick mesh is only deformed by tank deformation the water flowing through the mesh. The Lagrangian shell nodes still coincide with the material points and the elements deform with the material: this is known as a Lagrangian mesh. For the ALE mesh, nodes on the boundaries are fixed in order to remain on the border, while the interior nodes are moved.

 

The results will be continued in the following post.