2.25 Problem Sets - Section 5

Problem 5.8: Answer C

The answers given above are based on the assumptions that the secondary flow from compartment A to 1 is positive, and its volume flow rate is large compared with that injected at the jet. At Q=0, the secondary flow at 1 is in the negative direction, balancing exactly the positive volume flow of the jet. Clearly, both these assumptions are invalid and our solution does not apply. The minimum value of Q for this analysis to apply can be found by determining the value of Q that is just high enough that both of these assumptions are adequately satisfied.