Flow meter with adaptable beam characteristics

1. A method for measuring velocity of fluid flow in a channel, comprising:

transmitting, using a transmitter, directed energy carrying a signal toward a surface of a fluid in a fluid channel so as to produce a plurality of reflections, each of the plurality of reflections corresponding to one of a plurality of locations within the fluid channel, wherein the plurality of locations substantially span the entire width of the fluid channel;

detecting, using a plurality of measurement beams, a plurality of received signals, each of the plurality of received signals corresponding to one of the plurality of reflections;

determining, based upon differences between transmitted and the received signals, a plurality of localized velocities, each of the plurality of localized velocities corresponding to one of the plurality of locations; and

computing, from the plurality of localized velocities, a cross-sectional average velocity of fluid in the channel.

2. The method of claim 1 , wherein said plurality of localized velocities comprise a plurality of surface velocities.

3. The method of claim 1 , wherein the determining comprises determining a frequency difference between the transmitted signal and the received signals.

4. The method of claim 1 , wherein the plurality of measurement beams are oriented to detect and distinguish the plurality of reflections.

5. The method of claim 4 , wherein a sub-set of the plurality of localized velocities comprises velocities at surface locations that are regularly spaced about the centerline of the fluid surface.

6. The method of claim 1 , wherein the directed energy is selected from the group consisting of electromagnetic energy and ultrasonic energy.

7. The method of claim 1 , wherein the measurement beams are formed by one or more antenna arrays.

8. The method of claim 1 , wherein measurement beams of distinct orientations are formed simultaneously.

9. The method of claim 1 , wherein measurement beams of distinct orientations are formed sequentially.

10. The method of claim 1 , wherein the transmitter is mounted at the crown of a pipe.

11. A device for measuring velocity of fluid flow in a channel, comprising:

a transmitter;

using one or more receivers;

a processor operatively coupled to the transmitter and the one or more receivers;

a memory device that stores instructions executable by the processor to:

transmit, using the transmitter, directed energy carrying a signal toward a surface of a fluid in a fluid channel so as to produce a plurality of reflections, each of the plurality of reflections corresponding to one of a plurality of locations within the fluid channel, wherein the plurality of locations substantially span the entire width of the fluid channel;

detect, using a plurality of measurement beams, a plurality of received signals, each of the plurality of received signals corresponding to one of the plurality of reflections;

determine, based upon differences between transmitted and the received signals, a plurality of localized velocities, each of the plurality of localized velocities corresponding to one of the plurality of locations; and

compute, from the plurality of localized velocities, a cross-sectional average velocity of fluid in the channel.

12. The device of claim 11 , wherein said plurality of localized velocities comprise a plurality of surface velocities.

13. The device of claim 11 , wherein the instructions executable by the processor to determine comprises instructions that determine a frequency difference between the transmitted signal and the received signals.

14. The device of claim 11 , wherein the plurality of measurement beams are oriented to detect and distinguish the plurality of reflections.

15. The device of claim 14 , wherein a sub-set of the plurality of localized velocities comprises velocities at surface locations that are regularly spaced about the centerline of the fluid surface.

16. The device of claim 11 , wherein the directed energy is selected from the group consisting of electromagnetic energy and ultrasonic energy.

17. The device of claim 11 , wherein the measurement beams are formed by one or more antenna arrays.

18. The device of claim 11 , wherein measurement beams of distinct orientations are formed simultaneously.

19. The device of claim 11 , wherein measurement beams of distinct orientations are formed sequentially.

20. A product for measuring velocity of fluid flow in a channel, comprising:

a non-transitory storage medium having code stored therewith, the code being executable by a processor and comprising:

code that transmits, using a transmitter, directed energy carrying a signal toward a surface of a fluid in a fluid channel so as to produce a plurality of reflections, each of the plurality of reflections corresponding to one of a plurality of locations within the fluid channel, wherein the plurality of locations substantially span the entire width of the fluid channel;

code that detects, using a plurality of measurement beams, a plurality of received signals, each of the plurality of received signals corresponding to one of the plurality of reflections;

code that determines, based upon differences between transmitted and the received signals, a plurality of localized velocities, each of the plurality of localized velocities corresponding to one of the plurality of locations; and

code that computes, from the plurality of localized velocities, a cross-sectional average velocity of fluid in the channel.