Single beam/detector optical remote cross-flow sensor

Patent metadata

Field	Value
Publication number	US-9927457-B2
Application number	US-201414466131-A
Country	US
Kind code	B2
Filing date	Aug 22, 2014
Priority date	Aug 23, 2013
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

System and method for remotely sensing the cross-flow orientation of a fluid (including a gaseous fluid) over an extended range. A Fourier transform of beam wander of a single beam can be used to determine the orientation of the flow field. Many applications depend upon accurate flow orientation data to provide correct information such as, for example, citing of turbines on wind farms and atmospheric/ocean weather prediction.

First claim

What is claimed is:

1. A method for determining flow orientation in a turbulent fluid comprising:
projecting a light beam from a single beam light source through the turbulent fluid onto a position sensitive detector (PSD);
detecting, by a computer processor, beam wander as a centroid of the light beam on the PSD over a pre-selected time period from a plurality of different angles;
calculating, by the computer processor, Fourier transforms of the beam wander for the plurality of different angles on the PSD;
combining the Fourier transforms of the plurality of different angles to generate combined Fourier amplitudes, wherein regions of high Fourier amplitude in the combined Fourier amplitudes form a sinusoidal shaped Fourier amplitude band along an axis representing the plurality of different angles on the PSD;
determining, by the computer processor, a maximum Fourier amplitude along the sinusoidal shaped Fourier amplitude band that is at highest Fourier frequencies, wherein a selected angle of the plurality of different angles is associated with the maximum Fourier amplitude; and
using the selected angle of the plurality of different angles to generate a flow prediction.

2. The method as in claim 1 wherein the turbulent fluid is an ocean and the flow prediction is an ocean forecast.

3. The method as in claim 1 wherein the turbulent fluid is a planetary atmosphere and the flow prediction is a weather forecast.

4. The method as in claim 1 wherein the single beam light source is continuous.

5. The method as in claim 1 wherein the single beam light source is pulsing.

6. The method as in claim 1 wherein the single beam light source is a laser.

7. The method as in claim 1 wherein the single beam light source is a point source.

8. The method as in claim 1 wherein the single beam light source is a plain wave.

9. A computer system for determining flow orientation in a turbulent fluid comprising:
a position sensitive detector (PSD);
a single beam light source projecting a light beam through the turbulent fluid onto the PSD;
a monitor processor detecting beam wander as a centroid of the light beam on the PSD over a pre-selected time period from a plurality of different angles; and
a flow orientation processor:
calculating Fourier transforms of the beam wander for the plurality of different angles on the PSD;
combining the Fourier transforms of the plurality of different angles to generate combined Fourier amplitudes that are plotted as Fourier amplitudes, wherein regions of high Fourier amplitude in the combined Fourier amplitudes form a sinusoidal shaped Fourier amplitude band along an axis representing the plurality of different angles on the PSD;
determining a maximum Fourier amplitude along the sinusoidal shaped Fourier amplitude band that is at highest Fourier frequencies, wherein a selected angle of the plurality of different angles is associated with the maximum Fourier amplitude; and
using the selected angle of the plurality of different angles to generate a flow prediction.

10. The system as in claim 9 wherein the single beam light source is a continuous wave.

11. The system as in claim 9 wherein the single beam light source is pulsing.

12. The system as in claim 9 wherein the single beam light source is a laser.

13. The system as in claim 9 wherein the single beam light source is a point source.

14. A non-transitory computer readable medium having computer-executable program instructions embodied therein for determining flow orientation in a turbulent fluid model, the computer-executable program instructions when executed causing a computer processor to:
project a light beam from a single beam light source through the turbulent fluid onto a position sensitive detector (PSD);
detect beam wander as a centroid of the light beam on the PSD over a pre-selected time period from a plurality of different angles;
calculate Fourier transforms of the beam wander for the plurality of different angles on the PSD;
combine the Fourier transforms of the plurality of different angles to generate combined Fourier amplitudes that are plotted as Fourier amplitudes, wherein regions of high Fourier amplitude in the combined Fourier amplitudes form a sinusoidal shaped Fourier amplitude band along an axis representing the plurality of different angles on the PSD;
determine a maximum Fourier amplitude along the sinusoidal shaped Fourier amplitude band that is at highest Fourier frequencies, wherein a selected angle of the plurality of different angles is associated with the maximum Fourier amplitude; and
use the selected angle of the plurality of different angles to generate a flow prediction.

15. The non-transitory computer readable medium as in claim 14 wherein the single beam light source is continuous.

16. The non-transitory computer readable medium as in claim 14 wherein the single beam light source is pulsing.

17. The non-transitory computer readable medium as in claim 14 wherein the single beam light source is a laser.

18. The non-transitory computer readable medium as in claim 14 wherein the single beam light source is a point source.

Assignees

• Nootz Gero A
• Dalgleish Fraser
• Rhodes William T
• Hou Weilin
• Us Navy

Inventors

• Nootz Gero A
• Dalgleish Fraser
• Rhodes William T
• Hou Weilin

Classifications

• G01P13/02 Primary

  Indicating direction only, e.g. by weather vane · CPC title