Calculate Pressure Drop of Air Across an Opening

[Futsal1st]

How do I determine the pressure drop of air across an opening? For example if I have 3,000 L/s (3 m³/s) and an opening of 8.4 m² I know the velocity is 0.4 m/s. If the free area is 80%, the velocity increases to 0.45 m/s. What I'd like to cal is the pressure drop in each case.

Cheers

 

[russ_watters]

It would depend on the characteristics of the opening. Is it a louver of some sort? Can you test it?

 

[Futsal1st]

Its a louvred roller door.

 

[russ_watters]

Is it pre-manufactured? Can you look up its characteristics? And you didn't answer my other question...

 

[Futsal1st]

Sorry 'bout that.

Its a car park roller door that has small openings (almost rectangular)about 5mm high and 50mm long. It acts like a perforated panel between the outdoor and the car park.