It would seem that the generators would ruin the laminar flow at reduced
angles of attack, as in cruise?

Who are you? - Most posters sign their works of art.

 

"Seems" is not good enough.  We look for data, facts, tests, experiments..... not guesses.

 

As a former ground bound person who has learned that earthly experiences make for severe errors when applied to airborne circumstances requires actual tests, etc..... 

 

Vortex generators re enegrize and can re attach the airflow near the separation point.  The separation point changes with angle of attack.  If the carefully chosen height and chord relative placement of the generators can reach beyond the boundary layer air, it can keep the flow from early separation - thus increased performance (lift) at lower speeds (higher angles of attack).

 

NACA's turbulent flow wings worked too - they just were a bit draggy.

 

Why are the wing vg's in pairs at opposing 30 degree angles from the centerline? huh? huh? But generally not so on vertical surfaces? huh? huh?

 

Early wing tests had them all pointing inward 30 degrees - worked until the airplane was put in a slip - one wing had increased lift the other wing had much less - The roll component was exciting.  Vertical surfaces don't have a similar problem since re attachment of the air on both sides is the concern.

 

I still haven't heard from someone who has successfully used vgs on the 320/360 small tail vertical stab for greater rudder aurthority.  I tried it ( two different chord relative locations) and had imperceptible results.  I just moved on to other experiments after I found that I could generally control the direction with learned rudder skills rather than mechanical vgs.