It is a method to generate the potential function (velocity field and the stream function) for more complex flows. It is used when we have walls as boundaries. For example, the case of a circle in a free stream close to a wall, with the velocity vector of the free-stream parallel to the wall. The potential function for the circle of radius
with center at
in a free stream of speed
is
Now, we want to put a wall at
.
To obtain the potential function of the velocity field which respects the no flux boundary condition at the wall, we superimpose a dipole located at the mirror image (located at
)
of the dipole (located at
)
representing the actual circle, so we have
Timothy S Choe
2003-03-15