An experimental investigation of the character and decay of the asymmetrical swirling flow produced by a double right-angle bend in two perpendicular planes has been carried out. Axial velocities have been measured at a total of 36 points on three parallel chords on each of two measurement stations that were 9 diameters and 35 diameters downstream of the bend. The author describes an algorithm used to obtain a polynomial approximation to the measured axial velocity profiles and presents the results of this. The formulae are then used to carry out a theoretical study of the effects of these flow fields on electromagnetic and ultrasonic flowmeters. Guidelines for the installation of flowmeters are given in the light of this theoretical work and a review of the literature.