Measuring pressure along a circular wall of radius r = 12 cm deflecting a jet, Reynolds number 106 . The pressure begins to fall along an angle 9° (installing a transverse gradient), and the remains constant if the h/r ratio of the width of the deflected jet to the radius is less than 0.25 along an additional angle which is a "true Coanda effect", and finally increases back to the ambient pressure again over another angle 9°. If h/r is more than 0.5, no true Coanda effect occurs.