2D aerofoil fluid analysis - find velocity ratio I just wondered if you could help me out on this fluid mechanics question? 
I have worked through it myself but am very unsure of my answer (not yet found the pressure difference) 

the question is in two parts, and states a wake velocity profile equation at the end: 

My workings used the equation given for the wake profile, but am unsure on whether this is needed to be used to find a solution?
IS THIS METHOD WRONG BELOW??
The way I approached it was to look at overall mass flow, assume density is constant throughout then simply rearrange to get the ratio.
I approached this problem also assuming the wind tunnel is cylindrical, then for downstream I said that the mass flow rate is the mass flow rate due to velocity U1 (across the whole length 2H) minus the mass flow rate caused by the wake velocity profile (across 2b). I assume this to be incorrect, but am really confused at how it would be done. 
If you need visuals to how I did it to make it clear, ill be more than happy to write it out for you guys.
 A: If u want to find exit pressure of control volume you have consider, you can use Bernoulli equation since you know exit velocity profile. Since boundary layer is thin and no flow separation,  this flow is more or less irrotaional flow and I'm assuming the flow is steady.
$$ p_1 +\rho \frac{v_1^2}{2} =p_2 +\rho \frac{v_2^2}{2}$$
Here
$p_1$, $v_1$ are inlet velocity and pressure respectively. $p_2$ and $v_2$ are exit velocity and pressure.
Then the exist pressure equation is
$$ p_2 =p_1 -\rho \frac{U1}{2}\left(1+\frac{y}{b}\right)+\rho \frac{U_0^2}{2} $$
Please note that $p_2 \leq p_1$.
If u want the exact velocity profile then you should so small CFD simulation. Velocity profile you have consider may be valid upto $y^+$ = 5 (apprx.). For that u can refer fifth page of  following link. 
http://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&sqi=2&ved=0CDEQFjAFahUKEwjm8YWKx9nGAhUKo5QKHSRZDWI&url=http%3A%2F%2Fwww.mit.edu%2Fcourse%2F1%2F1.061%2Fwww%2Fdream%2FSEVEN%2FSEVENTHEORY.PDF&ei=Q3GkVabEE4rG0gSksrWQBg&usg=AFQjCNEHNG85udrczw4D6dgihi7eTPlyTQ&sig2=3_uDHoAEOyy9fmMoCXl2jg&bvm=bv.97653015,d.dGo&cad=rja
