Pipe with varying cross-section

Question 1, also Vt is different, 1m/s in initial solution, 3 m/s in boundary conditions. Shall we use 3 overall?

Question 1, also Vt is different, 1m/s in initial solution, 3 m/s in boundary conditions. Shall we use 3 overall?

Hi Stefano,

to question 1: Please use as initial solution the lower value with 6 m/s (and 1m/s for vt). This is on purpose. In general it is a good idea to be as close as possible to the final expected flow field. In practice the geometry is complex and we need to find a good compromise. For this particular case 23m/s would be a very suitable initial solution for the smaller pat of the pipe. In the larger part of the pipe a much lower value is more suitable. In general it is more robust for the simulation, if we choose as initial solution a value, which is rather on the lower side. For some applications it even make sense to initialize the domain with 0m/s.

To question 2: You can choose either of these. We can do this because we specify a constant value. Here it does not matter, if we specify in the cartesian system the constant value or in the cylindrical system the constant value. But your thought is right!

Best regards
Manuel