Week 9- Unsteady moving zones Approach

AIM:

To simulate the turbomachinery component using the Moving Mesh method in the transient state to understand the flow physics.

THEORY:

MOVING MESH APPROACH:

Moving mesh approach is used only for the unsteady phenomenon like,

• Vortex-induced flow.
• Interaction of vortex with bodies.

In Moving Mesh Approach,

• Mesh is moving.
• Topology of mesh changes with time.
• Control volume changes as mesh changes.
• It is an unsteady phenomenon.

PROCEDURE TO SET UP THA CASE FOR MOVING MESH METHOD:

GEOMETRY:

• First, import the mesh into fluent.
• Using the display option the mesh can be visualized.

TURBULENCE MODEL AND MATERIALS:

• In the viscous model k-epsilon, a realizable model is used.
• In materials for fluid air is used with constant parameters.

CELL ZONE CONDITION:

• In a cell, zone condition is used to define that the surface of the mesh is rotating or stationary.
• Here in this problem, we have three cell zone conditions and all the three-zone should be set at fluid type.

• In a rotating frame, the mesh motion option is used to rotate the mesh.
• The rotational velocity is 300rpm.

BOUNDARY CONDITIONS AND MESH INTERFACES:

• In boundary conditions inlet is set as a pressure inlet and the outlet is set as a pressure outlet.
• Check that all the boundary condition is set correctly.
• A Mesh interface is used to set the interface between two surfaces to flow the fluid.

SOLUTION METHODS AND RUN CALCULATIONS:

• In solution method, coupled solver with second-order up-wind is used.

• In run calculation, since the simulation is transient based the time step size(s) is 0.00024 s.
• The number of time steps is 1000 and the maximum number of iteration per time step is 40.

RESULTS:

Velocity Contour:

Vorticity Contour:

Total Pressure Contour:

Animation video for Velocity contour:

CONCLUSION:

From this simulation, we came to know how to set the mesh motion method and mesh interface.