Click Materials from the Setup tab:
Questions about applying settings?
To open the Material quick edit dialog, click Edit from the Materials context menu:
Type = Resistance
On the Material line, Click Edit...
On the Material Editor, enter the name Inlet-Filter in the Name field.
Select My Materials from the Save to database menu.
Click the Through-Flow K button
Variation Method = Constant
Value = 50
Click Apply.
Click the Normal direction 1 K button
Value = 100000
Click Apply.
Click the Normal direction 2 K button
Value = 100000
Click Apply.
Click Save.
Click OK.