Guys, Let's not get too technical for KR work here. It's real simple flow goes from high pressure to low pressure. A NACA duct is good for capturing total pressure from a flow or returning total pressure to a flow (reverse placement to outflow back to the free stream).
Where is the high pressure and where is the low pressure? Once you know that then you can maximize the flow from high to low! What's all this suck blow stuff anyway? The problem here is the terms being used, not the engineering. Regards, Bob Lee N52BL KR2 Suwanee, GA 91% done only 65% to go!