Method of and apparatus for controlling the boundary layer flow over the surface of a body

• US 4,516,747 A
• Filed: 08/02/1983
• Issued: 05/14/1985
• Est. Priority Date: 08/03/1982
• Status: Expired due to Term

• Current Assignee: Messerschmitt-Bolkow-Blohm Gesellschaft
• Original Assignee: Messerschmitt-Bolkow-Blohm GmbH
• Inventors: Lurz, Werner
• Primary Examiner(s): Barefoot, Galen L.
• Application Number:
  US06/519,689
• Time in Patent Office: 651 Days
• Field of Search: 244/130, 244/204, 244/205, 114/67 R
• US Class Current: 244/204
• CPC Class Codes: B64C 2230/02 by using acoustic waves generated by transducers
• CPC Class Codes: B64C 23/00 Influencing air flow over aircraft surfaces, not otherwise provided for
• CPC Class Codes: F15D 1/12 by influencing the boundary layer
• CPC Class Codes: Y02T 50/10 Drag reduction

Abstract

In controlling the boundary layer of flow over the surface of a body, for reducing resistance and impeding flow separation, a sensor element in the surface measures certain flow values in the boundary layer. The measured values are conveyed to an analyzer control circuit which, in turn, conveys a signal to an active vibration transmitter in the surface of the body for providing the required control.

Claims

1. Method for controlling the flow in the boundary layer at the surface of a body cover which flow takes place, based on the active change of the original motion of flow particles in close proximity to the surface, comprising the steps of continuously measuring at least at two locations at least two of the physical values of the flow, as the frequency spectrum, the amplitudes and/or the phase position of the fluctuation velocities, directing the measured values to a control circuit, analyzing the measured values in the control circuit and determining the predominant frequency, and, based on the predominant frequency, transmitting a corresponding vibration signal to an active vibration transmitter located on the surface over which the flow takes place, and locating the measuring locations one adjacent to and upstream from the active vibration transmitter and the other adjacent to and downstream from the active vibration transmitter.

2. Apparatus for controlling flow in the boundary layer of the surface of a body over which flow takes place, based on the active change of the original motion of the flow particles in close proximity to the surface, comprising at least two passive sensor elements located in the surface of the body spaced apart in the direction of flow over the surface of the body, at least one active vibration transmitter located in the surface of the body between said at least two sensor elements, an analyzer control circuit connected to said at least two sensor elements and to said vibration transmitter so that the measurement effected by said sensor elements is transferred to said circuit where it is analyzed and based on the predominant frequency measure by said sensors a correcting signal is transmitted to said vibration transmitter for controlling the flow conditions within the boundary layer flow over the surface of the body.

3. Apparatus, as set forth in claim 2, wherein said sensors comprise at least one of a mechanical pressure receiver, a piezo crystal, an inductive receiver, a hot film, and the like.

4. Apparatus, as set forth in claim 2, wherein said vibration transmitter comprises at least one of a vertically oscillating surface part, an electromagnetic field, an electrically conducting surface area, piezo crystal, a a hot film and the like.

5. Apparatus for controlling flow in the boundary layer of the surface of a body over which flow takes place, based on the active change of the original motion of the flow particles in close proximity to the surface, comprising at least two passive sensor elements located in the surface of the body, at least one active vibration transmitter located in the surface of the body, an analyzer control circuit connected to said sensor elements and to said vibration transmitter so that the measurement effected by said sensor elements is transferred to said circuit where it is analyzed and a correcting signal is transmitted to said vibration transmitter for controlling the flow conditions within the boundary layer flow over the surface of the body, and a plurality of said sensors and a plurality of said vibration transmitters are combined as a unit ready to be installed with said sensors and vibration transmitters alternating one after the other in the direction of flow over the surface of the body.