Abstract: A process and arrangement for producing a strong turbulence in at least one fluid or quasi-fluid medium wherein the medium flows along at least two confined and adjacent stream paths, the streams being rotated in opposite directions within their paths so as to cause the flow components thereof to be directed opposite one another, and the streams laterally graze one another within a discharge chamber as they begin to move outwardly of their paths. The streams are suddenly brought into contact with each other within the chamber whereupon intensive movements of the medium particles develop transversely to the flow directions along fictitious planes of contact between the two streams as the result of a delay in speed of the flow components of the streams, whereby a strong turbulence develops with a most intimate mixing of the two streams.