Channel Flow using CONVERGE

Objective: To simulate the flow of fluid in a channel using CONVERGE for different mesh sizes.

Methodology:

The geometry is created using the create geometry option. The dimensions are as follows:

X: 0.1m Y:0.01m Z:0.01m.

The boundary conditions are applied to the surfaces as follows:

The Top and Bottom suffaces are given as Wall with a no slip boumdary condition.

The Inlet condition:

Pressure:100001Pa

Outlet condition:

Pressure:100000Pa

The front and back faces are given a 2D boundary condition.

The material is chosen as air with a composition O2:0.23 and N2:0.77

Three different grid sizes are taken

Grid 1: dx:2e-4 dy:2e-4 dz:2e-4

Grid 2: dx:1.5e-4 dy:1.5e-4 dz:1.5e-4

Grid 3: dx:1e-4 dy:1e-4 dz:1e-4

For the first grid size is run for 15000 cycles and the other two grids are run upto 50000 cycles to attain convergence.

Results:

Case 1:

The mesh is chosen Grid 1.

The cell count is as follows:

The velocity contour is as in the figure below

The graphical representation of velocity profile:

The pressure contour is as follows:

The mass flow rate is as follows

Case 2: Grid 2

The cell count is as follows:

The velocity profile and contour obtained is as follos:

The pressure contour is as follows:

The mass flow rates are obtained as follows:

Case 3: Grid 3

The mesh and cell count are as follows

The velocity profile and contour obtained are as follows:

The pressure contours obtained as follows:

The mass flow obtained at the inlet is as follows:

The animation of the flow through the channel can be seen in the link below. The initial oscillatory nature dies down and the simulation reaches the steady state.

Conclusion:

From the above contours the parabolic nature of flow can be seen. The contours get smoother as the mesh is finer. The mirror images of the mass flow rates show that mass is conserved.