Funny you should mention this. I just finished, today in fact, an air flow analysis of a product. Omega style air flow meter. Hot wire type. Measures in linear ft/min.
What I had to do was build from cardboard a long tapered cone (about 3 feet long) that I attached around the vents under analysis. It tapered down to a 1" x 4" slot. Did several measurements across the slot to get an average. I used the dimensions of the slot to convert to ft^3/min. Then, roughly to what that would provide as far as maximum wattage allowed by the air flow. The sensor of the device is on an extendable arm like an antenna. Highly accurate and very illumenating. - Doug McKean
