hi experts, I just came across a question while doing my analysis.
I need to analyze pipes connecting a heat exchanger and a vertical vessel, the line in question comes right up from heat exchanger then goes to vessel's nozzle which is a tangent nozzle, I got different vertical forces on the nozzle if I modeled the nozzle differently, one is as usual that the nozzle connects to vessel using rigid element the other is that the nozzle connects to vessel using pipe, the one using rigid element is much bigger than that of uing pipe;

so which one is more accurate? why is there the difference?

thanks in advance.