Interview question on Reynold's Number

[skywalker001]

Hi everybody,

I always thought that the last time I would have to fathom Reynold's Number was for ATP written exams but it seems this is not the case.

A particular airline has been asking interview questions relating to Reynolds Number recently. I understand that the number determines whether the flow of a fluid is turbulent or laminar. Does this mean that the Reynold's Number is directly proportional to Total Drag? In the instance of an aircraft on the wrong side of the drag curve, accelerating, will its Re decrease progressively until Vimd and then begin increasing?

My next question is this: What about high speed flight? The standard Reynold's Number explanation ignores the effects of compressibility. What happens when you're cruising at .78M? What happens to Re at Mcrit? No matter how many thermodynamics websites I visit and how many ATP text books I read, I can't figure this one out. Can any of you geniuses out these shed some light on this mysterious phenomenon for me (in simple terms, if there is such a thing)?

Thanks in advance!