Abstract: Methods for noninvasive determination of acoustical properties of flowing in pipes having a large ratio (>10) of pipe diameter to wall thickness, and in highly attenuating fluids are described. When vibrations are excited on the outer surface of the wall of a pipe, the resulting vibrations propagate directly through the wall in a normal direction and through the pipe wall as guided waves, appearing on the opposite side of the pipe. This dual path propagation through pipes, where guided waves take the circumferential path in the wall of the pipe and may interfere with the time of-flight measurement obtained from the direct path through the fluid, is at least in part resolved by subtracting the signal from the guided wave from the combined signal, thereby permitting improved observation of the direct path propagation through the fluid.

Abstract: Methods for noninvasive determination of acoustical properties of flowing in pipes having a large ratio (>10) of pipe diameter to wall thickness, and in highly attenuating fluids are described. When vibrations are excited on the outer surface of the wall of a pipe, the resulting vibrations propagate directly through the wall In a normal direction and through the pipe wall as guided waves, appearing on the opposite side of the pipe. This dual path propagation through pipes, where guided waves take the circumferential path in the wall of the pipe and may interfere with the time of-flight measurement obtained from the direct path through the fluid, is at least In part resolved by subtracting the signal from the guided wave from the combined signal, thereby permitting improved observation of the direct path propagation through the fluid.

Abstract: A compact, rugged and portable measurement cell design for the determination of sound speed in fluids at temperatures up to 250° C. and pressures up to 3,000 psi is described. Swept Frequency Acoustic Interferometry measurement for liquid sound speed determinations in liquids up to 250° C. is of both fundamental interest, as in the case of basic equations of state, and applied interest, such as for characterizing geothermal or petroleum down hole environments. Representative sound speeds for water, as a function of temperature and pressure, are in agreement with an internationally accepted standard for the sound speed of water.

Abstract: A compact, rugged and portable measurement cell design for the determination of sound speed in fluids at temperatures up to 250° C. and pressures up to 3,000 psi is described. Swept Frequency Acoustic Interferometry measurement for liquid sound speed determinations in liquids up to 250° C. is of both fundamental interest, as in the case of basic equations of state, and applied interest, such as for characterizing geothermal or petroleum down hole environments. Representative sound speeds for water, as a function of temperature and pressure, are in agreement with an internationally accepted standard for the sound speed of water.