Systems and methods of active control of surface drag using selective wave generation

Patent metadata

Field	Value
Publication number	US-11744157-B2
Application number	US-201916696810-A
Country	US
Kind code	B2
Filing date	Nov 26, 2019
Priority date	Nov 30, 2018
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

A system includes a surface, an actuator, and a controller. The surface has a fluid flowing over the surface. The actuator is coupled to the surface to move the surface relative to the fluid. The controller causes the actuator to cause the surface to generate a surface wave that modifies drag in the fluid. The actuator can cause the surface to generate a Love wave.

First claim

What is claimed is:

1. A system, comprising:
a surface having a fluid flowing over the surface;
a multiple layer stack comprising at least a first layer facing the fluid and a second layer on an opposite side of the first layer from the fluid, the first layer comprising the surface, the first layer having a different shear-wave speed than the second layer, the first layer made from a different material than the second layer;
an actuator coupled to the surface to move the surface relative to the fluid; and
a controller that causes the actuator to generate a love wave in a plane of the surface to modify drag in the fluid.

2. The system of claim 1 , wherein the controller is configured to control at least one of an amplitude, a wavelength, or a frequency of the love wave based on a parameter of the fluid.

3. The system of claim 1 , wherein the surface is defined by a film covering an inner surface of a body through which the fluid flows.

4. The system of claim 3 , wherein the body includes a pipe.

5. The system of claim 1 , wherein the surface is defined by a film covering an outer surface of a body configured to move through the fluid.

6. The system of claim 1 , wherein the actuator includes a plurality of electrodes.

7. The system of claim 6 , wherein the actuator includes a surface acoustic wave device.

8. The system of claim 1 , wherein the actuator includes a piezo-electric material.

9. The system of claim 1 , wherein the actuator is attached to less than a threshold fraction of the surface.

10. The system of claim 1 , wherein the actuator includes a plurality of electrodes arranged along one or more parallel axes.

11. The system of claim 10 , wherein the controller drives the plurality of electrodes to generate the love wave to include a standing wave.

12. The system of claim 1 , wherein the surface includes a semiconductor material that is doped to achieve a desired response to actuation by the actuator.

13. The system of claim 1 , wherein the actuator does not move the surface out of a plane of the surface.

14. The system of claim 1 , wherein the first layer has a shear-wave speed lower than a shear-wave speed of the second layer.

15. A system comprising,
a surface having a fluid flowing over the surface;
an actuator coupled to the surface to move the surface relative to the fluid; and
a controller that causes the actuator to cause the surface to generate a surface wave that modifies drag in the fluid,
wherein the actuator includes a plurality of electrodes arranged to generate a beat frequency based on a first frequency of operation of a first subset of the plurality of electrodes and a second frequency of operation of a second subset of the plurality of electrodes.

16. A method, comprising:
coupling an actuator to a surface having a fluid flowing over the surface, wherein the surface is provided as a first layer of a multiple layer stack, the first layer facing the fluid, the multiple layer stack comprising a second layer on an opposite side of the first layer from the fluid, the first layer comprising the surface, the first layer having a different shear-wave speed than the second layer, the first layer made from a different material than the second layer; and
causing, by a controller, the actuator to generate a love wave in a plane of the surface to modify drag in the fluid.

17. The method of claim 16 , further comprising controlling, by the controller, at least one of an amplitude, a wavelength, or a frequency of the love wave based on a parameter of the fluid.

18. The method of claim 16 , wherein the surface is defined by a film covering an inner surface of a body through which the fluid flows.

19. The method of claim 18 , wherein the body includes a pipe.

20. The method of claim 16 , wherein the surface is defined by a film covering a body configured to move through the fluid.

21. The method of claim 16 , comprising:
driving, by the controller, a plurality of electrodes of the actuator.

22. The method of claim 21 , wherein the actuator includes a surface acoustic wave device.

23. The method of claim 16 , wherein the actuator includes a piezo-electric material.

24. The method of claim 16 , wherein the actuator is attached to less than a threshold fraction of the surface.

25. The method of claim 16 , wherein the actuator includes a plurality of electrodes arranged along one or more parallel axes.

26. The method of claim 16 , comprising:
driving, by the controller, the plurality of electrodes to generate the love wave to include a standing wave.

27. The method of claim 16 , comprising:
driving, by the controller, a first subset of a plurality of electrodes of the actuator at a first frequency of operation; and
driving, by the controller, a second subset of the plurality of electrodes at a second frequency of operation to generate the love wave at a beat frequency corresponding to the first frequency of operation and the second frequency of operation.

28. The method of claim 16 , wherein the surface includes a semiconductor material that is doped to achieve a desired response to actuation by the actuator.

29. The method of claim 16 , comprising:
moving the surface, by the actuator, out of a plane of the surface by less than a thickness of the surface perpendicular to the plane.

Assignees

• Deep Science Llc

Inventors

• Wine David William

Classifications

• Y02T50/10

  Drag reduction · CPC title

• H10N30/802 Primary

  Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits · CPC title

• G01N29/022

  Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices (microdevices per se B81B) · CPC title

• H10N30/20

  with electrical input and mechanical output, e.g. functioning as actuators or vibrators · CPC title

• G01N2291/0422

  Shear waves, transverse waves, horizontally polarised waves · CPC title