The pressure distribution of Fig.1(b) has suggested the development of anemometers8 such that schematically shown in Fig. 2(a) where a channel coinciding with a diameter is drilled through the cylinder body and the pressure difference across the two channel ends is measured. The idea is using two distinct sensors with perpendicular diameters to determine the wind direction and speed. Unfortunately, as shown in Fig.2 (b), this possibility is prevented by the non monotonic dependence of pressure difference dependence on the angle θ in the interval 0-180º.
Fig