2D channel flow simulation for three different mesh sizes

AIM: To setup a 2D channel flow simulation in CONVERGE

Geometry: Rectangular Parallelepiped; Dimensions: X=0.1m,Y=0.01m,Z=0.01m;

mesh size:Mesh_3- dx=(1e-4); dy=(1e-4); dz=(1e-4);

Mesh_2- dx=(1.5e-4); dy=(1.5e-4); dz=(1.5e-4);

Mesh_1- dx=(2e-4); dy=(2e-4); dz=(2e-4);

mesh_3:

Pressure contour animation-https://youtu.be/_lvQ47IRD-g

Velocity contour animation -https://youtu.be/5LCvGwEyFk8

mesh_2:

Pressure contour animation-https://youtu.be/mdSNZfkXx3A

Velocity contour animation -https://youtu.be/731-IctIXOE

mesh_1:

Pressure contour animation-https://youtu.be/Dq9ShRbZbmw

Velocity contour animation -https://youtu.be/mcgjcrwEMmI

Observation-

PRESSURE-Initially all the regions(region0) were assigned with 101325 pa, once the simulation starts pressure at inlet and outlet are assigned to pressure values 100010 and 100000 pa, because of the pressure difference hence the flow starts and can be seen clearly in the animation.

VELOCITY- A parabolic flow pattern is observed inside the duct, The velocity of the air will be maximum at the center and equal to free stream velocity(V∞) and almost zero near the walls(Vo) because of the wall friction and this phenomenon is known as Boundary layer formation.

.The fluid takes a certain length to develop completely into a parabolic profile of velocity, this length is called the \'Hydrodynamic entrance length and after this length, it maintains this parabolic profile till the outlet which is called the fully developed region.

In the above animation the boundary layer is not clearly seen,this is because of high number of grids, less range of velocity scale.

For the above conditions parabolic profile can be significantly seen with relatively low number of grids by compromising accuracy.

mesh_3 picture:

link:https://drive.google.com/open?id=1Hmlq7USSNViElT3V10oEW4mFPk-HgbV6

Number of grids-101101;

mesh_2 picture:

link:https://drive.google.com/open?id=1fbl2Nhj93hOm_PYcntgGxfrXBdktG9dF

Number of grids -45550;

mesh_1 picture:

link:https://drive.google.com/open?id=1ZVDagZ4GB5OC_BtDbSoL7QeCy83eBQIu

Number of grids - 25550;

Comparitive plots

Avg Inlet Velocity:

https://drive.google.com/open?id=1YaG2Uuv8vsbqRKYFGR0xZ5BcUVWW5avE

Avg Outlet Velocity:

https://drive.google.com/open?id=1nT0pSNHXgbcn-s5jQbYxRAsYivZOr6eW

Observation: In Inlet Velocity plot it is seen that the peaks of the curves are mostly more on positive side above the convergence line this signifies that fluid flow is along the normal vector of the inlet surface

contrary is also true, the peaks of the curves are below the convergence line signifying fluid flow is away from the normal to the outlet surface.

Curves of this nature are also seen in mass flow rate.

Inlet Mass flow_rate:

link:https://drive.google.com/open?id=1Sw-Zbg8OXl85oaP_GlpED0P363-atTUu

Outlet Mass flow_rate:

link:https://drive.google.com/open?id=1z6bdq7hzkwYdIwBwidEr1ZM2WcM3UNQZ

Inlet pressure:

link:https://drive.google.com/open?id=1ey7wtl5f5PNFAEI5SyDwmahgyF0IjvyI

Outlet pressure:

link:https://drive.google.com/open?id=1ayJg-1QRbgVKxQTxoFY2UBperqbIGwSW

Conclusion:-For all the above curves in the plots the

order of convergence-mesh_1>mesh_2>=mesh_3

In all the plots mesh_1 curves converge at less number of cycles whereas other curves shows deviation more compared to mesh_1.

CELL COUNT PLOT:

mesh_3:

link:https://drive.google.com/open?id=1QgeDm9S566u68NFFPkkwZvy-zqjop5cW

mesh_2:

link:https://drive.google.com/open?id=11OvWDBUiaLW5dInsDbWpoWQsgtJfzytl

mesh_1:

link:https://drive.google.com/open?id=11YwFHXnKojUmmHhSDEnhcL1RxOsn20IE

cell count- mesh_3>mesh_2>mesh_1