1. A method for determining the rheological parameters of a flowing fluid, in particular a suspension or emulsion, wherein the fluid flow is limited at least in partial areas by a wall in contact with the fluid, and wherein the method comprises the following steps: a) sending into the fluid flow an ultrasound signal transmitted from an ultrasound transmitter at least at one prescribed first frequency f 1 at an angle θ differing by 90° relative to the direction of flow; b) receiving into an ultrasound receiver an ultrasound signal reflected by particles entrained in the fluid in respective fluid areas with at least one second frequency f 2 that is characteristic for the respective fluid area and shifted relative to the frequency f 1 by a respective frequency shift Δf; c) acquiring the local wall thrust stress in at least an area of the fluid contacting the wall; d) calculating the at least one frequency shift Δf using the at least one first frequency f 1 and the at least one second frequency f 2 ; e) allocating the respective frequency shift Δf to a respective fluid area using the respective running time of the ultrasound signal between the point of transmission from the ultrasound transmitter and point of reception by the ultrasound receiver; f) calculating the fluid velocity of the respective fluid area in which the reflecting/particles are entrained using the respective frequency shift; and g) calculating rheological parameters of the fluid using the wall thrust stress of the fluid acquired in the at least one local wall area and the calculated fluid velocity of the respective local fluid areas of the flowing fluid.