this is a good question; and is taught with the wrong approach through most of the academic and industrial institutions.
for this u need to do a simple exercise. take 2 sheets of paper (A4 size will do) and hold them parallely with both your hands with about 2-3 inchs gap. then blow air between the papers. instead of going apart, the papers will come together....
i.e. when you induce velocity between the papers by blowing air between them, the perpendicular pressure of static air is partially diverted parallely. i.e. the pressure energy is partially diverted by flow of air parallel to the face of the sheets of paper.
do this and you can revert back for further questions...
happy experimenting!!!