Channel flow simulation for different mesh sizes using CONVERGE
INTRODUCTION:
This simulation is carried out to analysis the flow through a rectangular channel. The mesh is created for 3 different grid sizes. The flow is generated along the +X direction. As a result,this is a 2D simulation because the flow characteristics are simulated along the XY plane. The geometry of the channel is a cross-section of 0.01 * 0.01 with a length of 0.1 m.
The Top and Bottom faces are assigned the Wall BC.
The Front and Back faces are given the 2D BC.
MESH GENERATED:
The flow is simulated for 3 base meshes
- dx = 2e-4m, dy = 2e-4m, dz = 2e-4m
- dx = 1.5e-4m, dy = 1.5e-4m, dz = 1.5e-4m
- dx = 1.2e-4m, dy = 1.2e-4m, dz = 1.2e-4m
-->Mesh 1(Coarse):
-->Mesh 2(Fine):
-->Mesh 3(even finer):
SETUP:
The simulation is carried out as a Steady state simulation with a predefined mixture of Air. The simulation is run for 15000 cycles as it is in steady state. The minumum time step is taken as 1e-9 sec and the maximum time step is given 1 sec. A Volumetric region is created from the domain and all the boundaries are assigned to this region. The inlet is given an INFLOW boundary condition at a pressure of 100001 Pa and temperature of 300 K. The outlet is assigned the OUTFLOW boundary condition with pressure 1 bar. The Walls are given a No-SLIP boundary condition. The other walls are assigned a TWO-D boundary condition as the flow is 2 dimensional. Laminar flow is considered as the Pressure difference for the inlet and the outlet is just 1 Pa. The temperature throughout the domain is taken as 300 K because no Energy equation is considered. The solution is initialised with Air(mass fraction:----->N2:0.77 and O2:0.23 ) at 300K and 1 bar. The simulation is run in parallel with 4 processors.
RESULT&DISCUSSION:
MESH-1
Here the \'bound_id_1\' and \'bound_id_2\' refers to the inlet and outlet boundaries respectively.
Velocity Magnitude:
Average Mass Flow Rate:
Total Pressure:
Velocity Contour:
Pressure Contour:
MESH2
Velocity Magnitude:
Average Mass Flow Rate:
Total Pressure:
Velocity Contour:
Pressure Contour:
MESH3
Velocity Msgnitude:
Average Mass Flow Rate:
Total Pressure:
Velocity Contour:
Pressure Contour:
The Coarse mesh is found to have achieved convergence during the run of 15000 cyc. The other two finer meshes need to run for longer time in order to converge.