Air data system for measuring fluid flow direction and velocity

• US 5,585,557 A
• Filed: 05/12/1995
• Issued: 12/17/1996
• Est. Priority Date: 05/12/1995
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Loschke, Robert C., Balena, Frank J., Revell, James D., Hickmon, Floyd O. III
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): Oen, William L.
• Application Number:
  US08/440,506
• Time in Patent Office: 585 Days
• Field of Search: 73/170.02, 73/170.14, 73/181, 73/178 T, 73/861.06
• US Class Current: 73/170.14
• CPC Class Codes: G01P 5/14 by measuring differences of pressure in the fluid

Abstract

The invention is a system for determining the physical characteristics of an incident fluid flow stream over a surface of a vehicle relative to an axis thereof, the apparatus. In detail, the invention includes at least one first pressure sensor mounted on the surface, the at least one first pressure sensor for receiving dynamic pressure signals generated by the convected boundary layer of the fluid flow stream and providing an output signal representative thereof. At least one array of second pressure sensors (pressure transducers) is positioned down stream of the at least one first pressure sensors, the second sensors of the at least one array each of said second pressure sensors providing a second output signal representative of the above pressure signals received thereby. A computer system is adapted to receive the first and second signals and to calculate the angular direction of the fluid flow relative to the axis and the velocity thereof.

Claims

1. A system for determining the physical characteristics of an incident fluid flow stream over a surface of a vehicle relative to an axis thereof, the system comprising:

at least one first hydrodynamic pressure sensor means mounted on the surface,

at least one array of second dynamic pressure sensor means mounted on the surface down stream of said at least one first sensor means;

said at least one first sensor means and said second sensor means of

said at least one array for sensing pressure fluctuations generated the fluid in the turbulent boundary layer of the fluid flow stream; and

providing first and second output signals, respectively, representative of the pressure fluctuations passing thereover; and

means to receive said first and second output signals and to determine the transit time of the pressure fluctuations measured over a discrete period time from said at least one first sensor means to each of said second sensor means of said at least one array and to calculate the convection velocity of the pressure fluctuations within the turbulent boundary layer of the fluid flow stream over the surface.

2. The system as set forth in claim 1 further comprising said means also for receiving said first and second output signals and calculating the angular direction of the fluid flow stream relative to the axis.

3. The system as set forth in claim 2 further comprising said means also for receiving said first and second output signals and calculating the free stream velocity of the fluid flow stream over the surface.

4. The system as set forth in claim 3 further comprising:

temperature sensing means for measuring the temperature of the fluid and providing a third output signal proportional thereto; and

said means also for receiving said third signal and calculating the speed of sound within said fluid medium.

5. The system as set forth in claim 4 further comprising:

static pressure sensing means for measuring the static pressure of the fluid and providing a fourth output signal proportional thereto; and

said means also for receiving said fourth output signal and calculating the barometric pressure altitude.

6. The system as set forth in claim 5 comprising said means further providing for the calculation of the free stream Mach number of the fluid flow stream over the surface.

7. A system for determining the physical characteristics of an incident fluid flow stream over a surface relative to an axis thereof, the system comprising:

at least one first hydrodynamic pressure sensor means mounted on the surface,

at least one array of second dynamic pressure sensor means mounted on the surface down stream of said at least one first sensor means;

said at least one first sensor means and said second sensor means of said at least one array for sensing pressure fluctuations generated within the fluid in the turbulent boundary layer of the fluid flow stream; and

providing first and second output signals, respectively, representative of the pressure fluctuations passing thereover; and

means to receive said first and second output signals and to determine the transit time of pressure fluctuations measured over a discrete period time from said at least one first sensor means to each of said second sensor means of said at least one array and to calculate the convection velocity of the pressure fluctuations within turbulent boundary layer of the fluid flow stream over the surface.

8. The systenn as set forth in claim 7 further comprising said means also for receiving said first and second output signals and calculating the free stream velocity of the fluid flow stream over the surface.

9. The system as set forth in claim 8 wherein the fluid is confined within a channel, or conduit or the like, said system further comprising only one first hydrodynamic pressure sensor means and only one array of second dynamic pressure sensor means with said array having only one sensor means.