Calibration technique of wall shear stress sensors using oscillating plate

Patent metadata

Field	Value
Publication number	US-11674872-B2
Application number	US-202016924808-A
Country	US
Kind code	B2
Filing date	Jul 9, 2020
Priority date	Jul 15, 2019
Publication date	Jun 13, 2023
Grant date	Jun 13, 2023

Abstract

Disclosed are a system and methods for calibrating wall shear stress sensors. The system includes an oscillating plate coupled to an actuator and mounted on a rolling elements, and one or more sensors coupled to a height adjusting device. The system can further comprise a height control rod coupled to a height control base and a sensor holder configured to house the one or more sensors and supported on a connector, the connector configured to be rotatably disposed about the height control rod. The system can be calibrated by causing the actuator to oscillate the oscillating plate at a frequency, sensing, using the one or more sensors, shear stress at a wall, the shear stress at the wall being associated with a velocity field, and determining a theoretical wall shear stress based on fluid properties, the frequency, and the height of the one or more sensors above the oscillating plate.

First claim

The invention claimed is:

1. A system for calibrating a wall shear stress sensor, the system comprising:
an oscillating plate coupled to an actuator and mounted on a reduced friction sliding device, wherein the oscillating plate is configured to generate a velocity field transmitted towards the one or more sensors; and
one or more sensors disposed a distance above the oscillating plate, at least one of the oscillating plate and the one or more sensors configured to be moveable to achieve the distance of the one or more sensors above the oscillating plate, the one or more sensors being configured to measure shear stress at a wall, the shear stress at the wall being associated with the velocity field.

2. The system of claim 1 , further comprising:
a height control rod coupled to a height control base; and
a sensor holder configured to house the one or more sensors and supported on a connector, the connector configured to be rotatably disposed about the height control rod.

3. The system of claim 2 , wherein the sensor holder comprises an annular rod that holds a cylindrical tubing configured to house the one or more sensors.

4. The system of claim 2 , further comprising:
at least one proximity sensor supported on one or more prongs extending from the sensor holder.

5. The system of claim 1 , wherein the actuator comprises one or more of a horizontal shaker, a waveform generator, a horizontal displacement device, and an electrodynamic device.

6. The system of claim 1 , wherein the one or more sensors are configured to confirm that a sensor position relative to a position of the oscillating plate is constant during use of the system.

7. The system of claim 1 , wherein the one or more sensors are configured to be calibrated using the system by at least:
causing the actuator to oscillate the oscillating plate at a frequency sufficient to generate the velocity field;
sensing, using the one or more sensors, the shear stress at the wall, the shear stress at the wall being associated with the velocity field; and
determining a theoretical wall shear stress based on the velocity field, fluid properties, the frequency of oscillation of the oscillating plate, and the height of the one or more sensors above the oscillating plate.

8. The system of claim 7 , wherein the fluid properties comprises fluid temperature.

9. A method comprising:
providing one or more sensors a height above an oscillating plate, the oscillating plate being disposed on a reduced friction sliding device and coupled to an actuator, the actuator being configured to cause the oscillating plate to oscillate relative to the one or more sensors;
causing the actuator to oscillate the oscillating plate at a frequency sufficient to generate a velocity field towards the one or more sensors;
sensing, using the one or more sensors, shear stress at a wall, the shear stress at the wall being associated with the velocity field; and
determining a theoretical wall shear stress based on the velocity field, fluid properties, the frequency at which the oscillating plate is oscillating, and the height of the one or more sensors above the oscillating plate.

10. The method of claim 9 , wherein the fluid properties comprise fluid temperature.

11. The method of claim 9 , wherein the one or more sensors are coupled to a sensor holder and supported on a connector, the connector being configured to be moveably coupled to a height control rod supported on a height control base.

12. The method of claim 11 , wherein the sensor holder comprises an annular rod that holds a cylindrical tubing configured to house the one or more sensors.

13. The method of claim 11 , wherein at least one proximity sensor is supported on one or more prongs extending from the sensor holder.

14. The method of claim 9 , wherein the actuator comprises one or more of a horizontal shaker, a waveform generator, a horizontal displacement device, and an electrodynamic device.

15. The method of claim 9 , wherein the one or more sensors are configured to confirm that a sensor position relative to a position of the oscillating plate is constant during use of the wall shear stress sensor.

16. A method comprising:
causing oscillation of an oscillating plate at a frequency and an amplitude, the oscillating plate being disposed a relative vertical distance from one or more sensors, wherein oscillating the oscillating plate at the frequency and the amplitude is sufficient to generate a velocity field that is transmitted towards the one or more sensors;
sensing, using the one or more sensors, shear stress at a wall, the shear stress at the wall being associated with the velocity field; and
determining a theoretical wall shear stress based on the velocity field, the frequency and amplitude of oscillation of the oscillating plate, and the relative distance of the one or more sensors from the oscillating plate.

17. The method of claim 16 , further comprising:
moving one or more of the oscillating plate and the one or more sensors to achieve one or more adjusted relative distances between the oscillating plate and the one or more sensors such that the oscillating plate is caused to generate one or more adjusted velocity fields when oscillating at the frequency;
sensing, using the one or more sensors, the shear stress at the wall, the shear stress at the wall being associated with the one or more adjusted velocity fields;
determining a line of best fit through the velocity field and the one or more adjusted velocity fields; and
determining an adjusted theoretical wall shear stress based on the velocity field, the one or more adjusted velocity fields, the frequency and amplitude of oscillation of the oscillating plate, the relative distance of the one or more sensors from the oscillating plate, the one or more adjusted relative distances of the one or more sensors from the oscillating plate, and the line of best fit through the velocity field and the one or more adjusted velocity fields.

18. The method of claim 16 , further comprising:
oscillating the oscillating plate at one or more adjusted frequencies and one or more adjusted amplitudes such that the oscillating plate is caused to generate one or more adjusted velocity fields when the one or more sensors are disposed the relative distance from the oscillating plate;
sensing, using the one or more sensors, the shear stress at the wall, the shear stress at the wall being associated with the one or more adjusted velocity fields;
determining a line of best fit through the velocity field and the one or more adjusted velocity fields; and
determining an adjusted theoretical wall shear stress based on the velocity field, the one or more adjusted velocity fields, the frequency and amplitude of oscillation of the oscillating plate, the one or more adjusted frequencies of oscillation of the oscillating plate, the one or more adjusted amplitudes of oscillation of the oscillating plate, the relative distance of the one or more sensors from the oscillating plate, and the line of best fit through the velocity field and the one or more adjusted velocity fields.

19. The method of claim 16 , further comprising:
determining one or more fluid properties of a fluid disposed between the oscillating plate and the one or more sensors; and
determining the theoretical wall shear stress based on the velocity field, the frequency and amplitude of oscillation of the oscillating plate, the relative distance of the one or more sensors from the oscillating plate, and the one or more fluid properties of the fl

Assignees

• Univ Florida

Inventors

• Freidkes Brett R
• Sheplak Mark

Classifications

• G01N2203/0025

  Shearing · CPC title

• G01N3/62 Primary

  Manufacturing, calibrating, or repairing devices used in investigations covered by the preceding subgroups · CPC title

• G01L25/00 Primary

  Testing or calibrating of apparatus for measuring force, torque, work, mechanical power, or mechanical efficiency · CPC title

• G01N3/24

  by applying steady shearing forces (G01N3/26, G01N3/28 take precedence) · CPC title

• G01N2203/04

  Chucks, fixtures, jaws, holders or anvils · CPC title