The pressure distribution in the area of the hole and in its vicinity
does not follow this trend as the hole is exposed to atmospheric
pressure transversely, in this case 0 Pa gauge. The pressure loss due
to the hole is higher than the frictional loss along the length of the
duct as the distance between the center of the duct and the outside
of the leak is small compared to distance to the outlet where a 0 Pa
pressure boundary condition has been imposed. The bump in the
graph indicates the sudden surge in pressure loss due to the leak
(Fig. 6). Flow separation and hence loss of momentum causes a large
pressure drop at the leak.