sonic section before and after a shock !!
Hi every body
A sonic area in a CD nozzle can only exist when M=1 . It is the throat of the nozzle . When M=1 , we have a shock .
Imagine together that we have a normal shock NS just before the exit of the nozzle . My question is :
Is it true to say that we have a sonic throat upstream NS , it 's area is A1* ? ( with A1* = At , At is the throat of the nozzle )
Is it true to say that we have a sonic throat downstream NS , it 's area is A2* ?
At my opinion , we can only talk about a sonic area A* exactly where the normal shock takes place ( not before , not after NS) .
Thanks you for help , it seems that i am confused