Patent ID: 8602684

Claim:
An arrangement for producing linear standing waves in a flowing medium having a flow direction, said arrangement comprising: a transverse structure arranged at least substantially perpendicular to the flow direction, the transverse structure being designed such that an outflow is converted from a streaming flowing movement into a shooting flowing movement, a ramp connected downstream of the transverse structure, the ramp having an upper surface being inclined at least substantially in the flow direction, a counter-ramp arranged at least substantially in the flow direction at a downstream end of the ramp, the counter-ramp having an upper surface having an average inclination in the flow direction and in which the upper surface of the ramp and the upper surface of the counter-ramp form an angle less than 180° and the counter-ramp having a flow-promoting transition to the ramp at an upstream end, and a base arranged downstream of the ramp and the counter-ramp, and having a bottom which is arranged lower by a height dimension than the downstream end of the ramp and/or upstream end of the counter-ramp; wherein the counter-ramp has a rigid plate-like structure hinged on the downstream end of the ramp and an angle adjustment mechanism, and wherein a flexible plate-like structure is arranged in the flow direction over the rigid plate-like structure of the counter-ramp, the flexible plate-like structure has at its upstream end a tangential transition to the plate-like structure of the counter-ramp.