Ok, let's find the complex potential just to get you going

If , we have

, so q is a model flow.

Now to find the complex potential , we find its real part as the function to satisfy . The first equation gives , and substituting into the second one we get or , so and .

Now we find the streamline function as the imaginary part of . Since and are conjugate harmonic, we get that .

The first one gives or , and by substituting this into the second one , from which and finally .

We obtain the complex potential as .

Now set constant for the equation of streamlines, etc.