Vibration-driven acoustic jet controlling boundary layer separation

A structure having a surface with an aerodynamic profile;

• said structure, when operating in at least one regime of its intended use, vibrating consistently with modes of vibration including one mode vibrating within a band of frequencies containing a significant fraction of the vibrational energy of said modes of vibration;
• said surface, when said structure is operating in said at least one regime, having fluid flow adjacent said surface subject to boundary layer separation;
• said structure having a chamber disposed adjacent to a boundary layer separation point of said surface, one wall of said chamber comprising a resilient membrane having a concentrated mass disposed thereon and capable of oscillating at a frequency excitable by said band of frequencies in response to said vibration;
• and
• a nozzle connecting said chamber with said surface, vibration of said structure when operating in said at least one regime causing said mass to oscillate at frequencies related to said band of frequencies, thereby producing oscillatory pressure variations in said chamber at frequencies related to said band of frequencies which in turn provides pulses of fluid particles into the boundary layer of said surface at frequencies related to said band of frequencies.