Ventilation device for generating uniform fluid flows, and a drive unit for a device of said type

A device for generating a directed fluid flow, particularly a directed air flow, by moving an active element with an active surface in a fluid, having a support structure;

• a rotary structure, which is rotatably supported around a first axis of rotation relative to the support structure;
• and at least one active element with an active surface, which is mounted on the rotary structure and rotatably supported around a second axis of rotation;
• wherein the at least one active element is operatively connected to the rotary structure and the support structure in such a manner that, when the rotary structure rotates in relation to the support structure around the first axis of rotation by a first frequency of rotation f1, the at least one active element rotates in relation to the rotary structure around the second axis of rotation by a second speed of rotation f2, wherein the ratio between the first and the second frequency of rotation is more than 1, preferably ≧1.5, and especially preferred ≧1.7.