A Cobra probe is a device to measure the

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and eve ...

and

velocity Velocity is a measurement of speed in a certain direction of motion. It is a fundamental concept in kinematics, the branch of classical mechanics that describes the motion of physical objects. Velocity is a vector (geometry), vector Physical q ...

components of a moving

fluid In physics, a fluid is a liquid, gas, or other material that may continuously motion, move and Deformation (physics), deform (''flow'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are M ...

. It is a multi-holed pressure probe with rotational axis of the probe shaft coplanar with the measurement plane of the instrument. Because of this geometry, when the instrument is rotated around the shaft's axis, the measurement elements of the probe remain in the same location. The name cobra probe comes from the shape of the probe head which gives it this property. Cobra probes come in three-, four-, and five-hole configurations, the former used for two-dimensional flow measurement, the latter two for three-dimensional flow measurement. In the three-hole kind of instrument, there are two yaw direction tubes which are chamfered and

silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...

soldered symmetrically on the two sides of a pitot tube. It is otherwise similar to the other kinds of yawmeters. In the four- and five-hole configurations, the central pitot tube is surrounded by three or four chamfered tubes, respectively.

References

Hydraulic engineering {{Tool-stub