Abstract: An apparatus for use in an industrial process for measuring a velocity of a fluid moving in a pipe includes a probe disposed in said fluid flow. The probe includes a tube and an array of at least two sensors disposed at different axial locations along the tube. Each sensor measures inhomogeneous pressure disturbances at respective axial locations. Each sensor further provides a pressure signal. The apparatus also includes a signal processor, responsive to the pressure signals, to provide a signal indicative of the velocity of the fluid. In one embodiment, the sensors filter out wavelengths above a predetermined wavelength. At least one of the sensors comprises a strain gage disposed on a surface of the pipe. In one embodiment, the strain gage comprises a fiber optic strain gage. The apparatus may be configured to detect the velocity of any desired inhomogeneous pressure field in the flow.

Abstract: Low-loss large diameter optical waveguide attachment devices (i.e., pigtails) and methods and systems of making the same are provided. The optical waveguide attachment devices may include an optical fiber (or other type waveguide) embedded in a larger diameter carrier tube. According to some embodiments, multiple laser beams (from one or more laser) may be utilized to uniformly heat the circumference of the carrier tube. According to some embodiments a maria may be formed in one end of the capillary tube to facilitate optical waveguide insertion and/or provide strain relief.

Abstract: Flow rate measurement system includes two measurement regions 14,16 located an average axial distance ?X apart along the pipe 12, the first measurement region 14 having two unsteady pressure sensors 18,20, located a distance X1 apart, and the second measurement region 16, having two other unsteady pressure sensors 22,24, located a distance X2 apart, each capable of measuring the unsteady pressure in the pipe 12. Signals from each pair of pressure sensors 18,20 and 22,24 are differenced by summers 44,54, respectively, to form spatial wavelength filters 33,35, respectively. Each spatial filter 33,35filters out acoustic pressure disturbances Pacoustic and other long wavelength pressure disturbances in the pipe 12 and passes short-wavelength low-frequency vortical pressure disturbances Pvortical associated with the vortical flow field 15. The spatial filters 33,35 provide signals Pas1,Pas2 to band pass filters 46,56 that filter out high frequency signals.

Abstract: Flow rate measurement system includes two measurement regions 14,16 located an average axial distance ?X apart along the pipe 12, the first measurement region 14 having two unsteady pressure sensors 18,20, located a distance X1 apart, and the second measurement region 16, having two other unsteady pressure sensors 22,24, located a distance X2 apart, each capable of measuring the unsteady pressure in the pipe 12. Signals from each pair of pressure sensors 18,20 and 22,24 are differenced by summers 44,54, respectively, to form spatial wavelength filters 33,35, respectively. Each spatial filter 33,35 filters out acoustic pressure disturbances Pacoustic and other long wavelength pressure disturbances in the pipe 12 and passes short-wavelength low-frequency vortical pressure disturbances Pvortical associated with the vortical flow field 15. The spatial filters 33,35 provide signals Pas1,Pas2 to band pass filters 46,56 that filter out high frequency signals.

Abstract: Flow rate measurement system includes two measurement regions 14,16 located an average axial distance &Dgr;X apart along the pipe 12, the first measurement region 14 having two unsteady pressure sensors 18,20, located a distance X1 apart, and the second measurement region 16, having two other unsteady pressure sensors 22,24, located a distance X2 apart, each capable of measuring the unsteady pressure in the pipe 12. Signals from each pair of pressure sensors 18,20 and 22,24 are differenced by summers 44,54, respectively, to form spatial wavelength filters 33,35, respectively. Each spatial filter 33,35 filters out acoustic pressure disturbances Pacoustic and other long wavelength pressure disturbances in the pipe 12 and passes short-wavelength low-frequency vortical pressure disturbances Pvortical associated with the vortical flow field 15. The spatial filters 33,35 provide signals Pas1,Pas2 to band pass filters 46,56 that filter out high frequency signals.