Abstract: A pyroelectric swirl indicator for measurement of swirl in flowing fluid comprising at least one pyroelectric substrate having at least one surface to which is applied a fluctuating heat input, the fluctuating heat input causing a fluctuating surface charge distribution in response to temperature fluctuations of the substrate. Spaced apart conductor elements for sensing the fluctuating surface charge on the surface of the substrate in the vicinity of the spaced apart conductor elements are provided, the differences in the charge fluctuations between the spaced apart conductor elements comprising an indication of swirl flow in the fluid, said spaced apart conductor elements disposed in a manner which enables measurement of orthogonal components of fluid flow.