[sadjad]

Hi guys

We have a flume that want to run turbidity flow. This flume has a sluice gate or valve. Behind the sluice gate there is salty water and in front of it there is water. With suddenly removal of sluice gate the salty water runs into the water. (Turbidity flow)

Length of flume: 500 cm

Width of flume: 35 cm

Height of flume: 70 cm

Height of free surface: 66 cm

Height of air in the flume: 4 cm

Attention: flow is free surface.

Now there is the main question in CFX that if we should define two fluid (Water & salty water) with section 66*35 or three fluid with section 70*35 (Water & salty water & air)?

And in the case of tree fluid with section 70*35 (Water & salty water & air) the expression of the air how could be defined or written? I cannot write it.

Please help me.