Simulation of Channel Flow using Converge

Open-Channel Flow

Open channel flow is a type of fluid flow with at least one free surface subjected to the surroundings. The pressure is considered to be constant at the surface and hydraulic streamlines are at the surface of fluid in open channel flow. The water in the open channel is not fully covered by the rigid boundaries. This is because a minimum of a single portion of channel will be of free surface which is visible to the atmosphere. The open channel flows are established in both small and large-scale applications.

The open channel flow is dependent of below properties,

• Cross-section of the channel

• Velocity of fluid flowing inside a channel

• Depth of flow

When compared to pipe flow, the open channel flow has gravitational force. The open channel flow can be of any shape or size depending upon the type of fluids and their properties. Also, it has very high velocity of fluid at a smaller distance below the water surface than that of the pipe flow. The boundary conditions are commonly obtained by the environmental pressure at the free surface.

The main disadvantage of open channel flow is the fluid flow conditions, because of the existence of free surface which will alter in relation to time and surroundings. In engineering, it is too complex to solve the fluid mechanics problem in the open channel flow. The roughness treatment in open channel flow also has major issues when compared to the pipe flow.

Simulation Parameters

Assuming the fluid inside the channel to be an Air mixture having 23% of Oxygen and 77% of Nitrogen and the initial conditions to be same as that of the inlet section.

Boundary Conditions

• Inlet Pressure = 100001 Pa
• Outlet Pressure= 100000 Pa
• Top and Bottom walls= No-Slip walls
• Front and Back Walls= 2D

Run Parameters

• Solver = Pressure Based Steady Solver

Contours

• Mesh Size 0.3mm

• Mesh

• Pressure Contour

• Velocity Contour

• Animation

https://youtu.be/q7l1Rmm1toE

• Mesh Size 0.25mm

• Mesh

• Pressure Contour

• Velocity Contour

• Animation

https://youtu.be/zVYwYcRQ9Zk

• Mesh Size 0.2mm

• Mesh

• Pressure Contour

• Velocity Contour

• Animation

https://youtu.be/PLkakZQWfB4

Plots

• Inlet Velocity Profile

• Outlet Velocity Profile

• Inlet Mass Flow Rate Profile

• Outlet Mass Flow Rate Profile

• Inlet Static Pressure Profile

• Outlet Total Pressure Profile

• Total Cells

The gas flow reaches the steady state in around 25000 cycles.