Lift of Half Cylinder

It is instructive to compute the lift of a half cylinder (of unit radius) glued to a half plane:

By symmetry the pressure is the same as for a full cylinder, that is on the cylinder surface the pressure is given by

• for ,

and thus the lift force is given by

• = 1.67,

which gives a lift coefficient since the planform width of the cylinder is 2.

We compare with the maximal about 1.5  from measurements:

Not so bad!! You may think of the half cylinder as a sort of wing:

 

for which you have just computed the lift to be L = 1.67.