Hi,
I am modeling a transient flow through a straight flexible pipe in Fluent. I got the experimental data: time-varying velocity at inlet, time-varying pressure at the inlet, time-varying pressure at the outlet.
I have to decide what fluid boundary condition to use. The time-variance is realized by the UDF define_profile.<\/p>\n
I tried with the velocity-inlet and pressure-outlet. I monitor the calculated inlet pressure, and it differs very much from the experimental data – it is almost equal to the imposed pressure at the outlet.
So I tried with the pressure-outlet and pressure-inlet BC, where for the inlet I calculated the total pressure (static pressure+dynamic pressure, anyway dynamic pressure was negligible). In such model I got much discrepancies in calculated velocity at the inlet and measured velocity.<\/p>\n
So the question arises, how to properly specify the boundary conditions for this problem.
I found that in the pressure outlet panel, there is an option “target mass flow”, where I can specify the time-varying mass flow, determined based on the measured velocity time profile. Is this a proper solution? The measured velocity however, is at the inlet, not at the outlet… and they will not be equal because there is a mass accumulation in the domain.<\/p>\n
The best solution for me, will be to impose: at the inlet both the velocity and pressure time profile, and at the outlet, the pressure time profile. However as far as I know there is no possibility to impose both velocity and pressure at the inlet, and I don’t know why.<\/p>\n
Please guide me with this problem,
Regards<\/p>\n","protected":false},"template":"","class_list":["post-364056","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t