Question

For an isentropic flow, consider two points 1 and 2 along the flow. Select the incorrect statement out of the following.

(a) v1 = v2

(b) ρo,1 = ρo,2

(c) po,1 = po,2

(d) ho,1 = ho,2

I had been asked this question in an interview.

Enquiry is from Definition of Total Stagnation Conditions topic in portion Compressible Flow – Preliminary Aspects of Aerodynamics

Answer 1

Right choice is (a) v1 = v2

To explain: In isentropic flow, between any two points, the stagnation quantities are same. They are constant along the entire isentropic flow. Thus, ρo,1 = ρo,2; po,1 = po,2 and ho,1 = ho,2 while the velocities are not equal necessarily. So, V1 is not equal to V2.