flow resistance

Franco Belosi

hi I'm trying to simulate a sampler for environmental purposes. The flow should be forced to pass through a filter (where pollution will be captured) of 0.15 mm thickness and about 1330 Pa as a pressure drop with a fluid velocity of 1.45 cm/sec.By inspecting the Solver manual of CFX4.3 I set up the filter resistance by means of body forces (I would not be interested on the fluid behaviour inside the filter, but in the uniform distribution of the flux over the filter surface) which a huge value: around 10+08 kg/m3sec. The simulation diverges (apparently teh flow is forced back from the filter resistance). Perhaps my BC are wrongs: at the inlet I set a PRESSURE BC while at outlet (where there is the filter I set a uniform velocity). Anybody can give any suggestions?

Thank you

Franco Belosi