## THE PRESSURE FIELD

We can now evaluate the pressure field with the equivalence

where indicates the reference value of the pressure at infinity (where the flow is uniform).

In the picture the excess nondimensional pressure defined as

is shown.

When circulation is absent, the pressure field is symmetric with respect to to both the x and the y axes. On the stagnation points the excess pressure is positive (which means an action directed towards the body) while on the upper and lower points the excess pressure is negative (which means an action directed away from the body).

As circulation increases the pressure field is still symmetric with respect to the y-axis but becomes asymmetric with respect to the x-axis.