Using a Venturi to suck out boundary layer from wind tunnel?

[g-force_addict]

Using the air flow already created by the fans to divide the airflow in two sections a straight inner section and a (curved) Venturi outer section that sucks out the boundary layer thru holes in the test section area.

Something like this


Would this array need extra flow straighteners?
Does the straight tunnel section need to be longer approaching the fans to ensure consistent suction (as depicted in the image?

Any other improvements you would advice?
thanks guys