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.