I'm modeling a simple nozell to investigate an air amplification scheme. The input to the nozell is compressed air at about 100 PSI - I'm not sure what the best type of load to use for this - the fan surface doesn't seem to work well - If I use the Surface Pressure / Traction object - not sure which option to use - Static pressure or Total Pressure or other, like traction - can someone explain which of these options would work best for understanding resulting velocity and pressure out the end of the nozzel, and what traction pressure is ?
ps: here is a cross section of the model to show you inputs and outputs - red is input, both front and back of nozzel are inlet / outlets with no other constraints.
Solved! Go to Solution.
For this internal flow, same physical problem can be modelled either following two ways with the speficied BCs and the ways of validating result.
(a) Spcify Inlet pressure +outlet pressure, validate result at flow rate (or velocity)
(b) Specify inlet velocity (or flowrate) + outlet pressure(or inlet/outlet BC), validate average pressure drop from inlet to outlet
Numerically (b) is stable than (a), and one of the special case is setting outlet pressure=0 (or set inlet/outlet BC).
It appears that you have convergence issue according your posted image, I suggest that you change your modelling to (b) and make sure the mesh is good condition.