Hello. I am designing a drying mechanism for a window. Basically air is taken from the atmosphere by a vacuum pump and is ducted to a small width aperture. The aperture would be 18 inches long and as thin as we can make it (millimeters). Inspiration for this design is from the Dyson hand dryer which uses 400 mph sheets of air to blast water off hands. My question is when performing the calculations can i assume that flow is incompressible. I imagine i can not but this doe not have to be way too precise. I just need to know if it will remove water from the window. Calculations using conservation of mass with incompressible, uniform flow say that with my given vacuum pump the air velocity at the outlet will be 107 mph. I would appreciate any guidance in these calculations..