Patent ID: 7330797

Claim:
An apparatus for measuring a parameter of a flow passing through a pipe, the apparatus comprising: a first spatial array of at least two sensors disposed at different axial locations along the pipe, each of the sensors in the first array being positioned at a first radial location on the pipe and providing a first signal indicative of unsteady pressure created by coherent structures convecting with a portion of the flow passing through a first portion of the pipe; a second spatial array of at least two sensors disposed at different axial locations along the pipe, each of the sensors in the second array providing a second signal indicative of unsteady pressure created by coherent structures convecting with a portion of the flow passing through a second portion of the pipe, the first portion of the pipe being located above the second portion of the pipe; and at least one signal processor configured to: determine a first velocity of the flow passing through the first portion of the pipe using the first signals, determine a second velocity of the flow passing through the second portion of the pipe using the second signals, and compare the first and second velocities to determine the parameter of the flow.