I want to simulate a turbulent flow in a rectangular channel, what is the difference between pressure outlet and outflow in bondary condition.

The pressure outflow means, the flow at exist is monitored with some specified pressure... In this case, the flow may or may not achieve the fully developed state.

Outflow condition assumes a zero diffusion flux for all flow variables. Physically it is consistent with a fully-developed flow assumption, when there is no area change at the outflow boundary. In this, only the diffusion fluxes in the direction normal to the exit plane are assumed to be zero.

thank you, but in ma simulation the fully-developed flow is the boundary condition in outlet, so I want to use outflow.

[maysmech]

Hi,

If the case be multiphase which one should be used when we want exit of one of species to outlet.

regards.

[fazadzulhimam]

hi,
i was simulating circular pipe with L = 0.375 m and entrance length 1.1 m,
in the outlet of downstream i was defined with outflow, but i get negative pressure in result,
can someone help me please?

my simulation with velocity 3 - 8 in m/s

[Zaktatir]

Outflow condition assumes a zero diffusion flux for all flow variables expect the pressure. Your flow hast to fully developed. Furthermore the outflow Condition may be used if you do not know your pressure specification at exit and you want to make some weighting wither other exits. DO NOT USE if you have recirculations or pressure inlet-pressure outlet conidtions. The outflow is not trustfully if pressure level is known in the domain


keep it real