Gurus, I am reading a book in engine design and one of the first chapters is about air intakes.
1. The author mentions that the lips of commercial aircraft engines are thicker than those of military engines.
[ The silver part in the picture below]
The reason given is that in the static case, air is drawn from even behind the lips. This causes flow to separate because of extreme local acceleration inside the air-intakes near the lips ( Separated flow could damage the blades ). To prevent this, the lips are made thicker.
My question: how do they solve this flow separation in military engines?
2. This is something that I (possibly) realised after reading the book. In the same picture above, notice how the engine actually projects in front of the wing.? I think this is to avoid a distorted air-flow from entering the intakes...correct?. The book says that pylons, wings and fuselage all distort the flow. So I assume the the MD DC-10 would have had this distorted flow in the engine in the middle.
Also, I read that in the static case, vortices tend to form because of the ground below when the engine is idling. This problem vanishes when the aircraft is accelerating.