* From Small Disturbances
: (subsonic)
* From Divergence Theorem
* Let Velocity U be a twice continuously differentiable function in a region of volume V in space.  This function is the stream function .
* Let P be a point in the volume V
* Let S be the surface boundary of the volume V.
* Let Q be a point on the surface S, and .
As Q goes from inside V to the surface of V, 
* Therefore:
For :, where the surface normal points inwards.
This equation can be broken down into both a source term and a doublet term.
The Source Strength at an arbitrary point Q is:
The Doublet Strength at an arbitrary point Q is:
The simplified potential flow equation is:
With this equation, along with applicable boundary conditions, the potential flow problem may be solved.