Clamp-on ultrasonic flow metering is provided by collectively exciting and receiving circumferential modes of the pipe. The pipe wall supports an infinite number of circumferential acoustic resonances. Each of these modes, in contact with a fluid, can mode-convert into the flow at a different rate. The mode-converted waves in the flow mode-convert back into the circumferential waves in the pipe once they travel across the flow. Furthermore, the moving fluid alters the rate of mode-conversion as a function of the flow velocity. At low frequencies, the wavelength is larger, thus the penetration depth in the flow is larger. As the frequency increases, the penetration depth becomes smaller. The variable penetration depth provides a methodology to sample the flow velocity profile.

A flow rate measurement apparatus includes first and second transducers provided at different positions in a longitudinal direction of a pipe, the at least two transducers including first and second transducers. The flow rate measurement apparatus further includes a transmitter and receiver. The transmitter transmits a transmission signal, which is an ultrasonic signal having a band wider than the ultrasonic signal, or a plurality of ultrasonic signals having a plurality of different frequency ranges. The receiver separates a target signal passing through a fluid from the received signal by utilizing that an attenuation rate of the ultrasonic signal in the fluid in a predetermined frequency band is different from an attenuation rate of the ultrasonic signal in the pipe in the frequency band, and measures a flow rate based on a separated target signal.

A flow rate measurement apparatus includes first and second transducers provided at different positions in a longitudinal direction of a pipe, the at least two transducers including first and second transducers. The flow rate measurement apparatus further includes a transmitter and receiver. The transmitter transmits a transmission signal, which is an ultrasonic signal having a band wider than the ultrasonic signal, or a plurality of ultrasonic signals having a plurality of different frequency ranges. The receiver separates a target signal passing through a fluid from the received signal by utilizing that an attenuation rate of the ultrasonic signal in the fluid in a predetermined frequency band is different from an attenuation rate of the ultrasonic signal in the pipe in the frequency band, and measures a flow rate based on a separated target signal.

A method of determining a measure of wave speed or intensity in a fluid conduit uses ultrasound measurements to determine the conduit diameter and fluid velocity in a volume element, each as a function of time, and each at a same longitudinal position of the conduit. The ultrasound measurement to determine fluid velocity is effected by tracking objects within the fluid flow in successive frames sampling the volume element, and obtaining displacement vectors for the objects. A wave speed may be determined from a ratio of the change in fluid velocity at the longitudinal position as a function of time and the change in a logarithmic function of the conduit diameter as a function of time. A measure of wave intensity may be determined as a function of change in determined conduit diameter and corresponding change in fluid velocity.

A method of determining a measure of wave speed or intensity in a fluid conduit uses ultrasound measurements to determine the conduit diameter and fluid velocity in a volume element, each as a function of time, and each at a same longitudinal position of the conduit. The ultrasound measurement to determine fluid velocity is effected by tracking objects within the fluid flow in successive frames sampling the volume element, and obtaining displacement vectors for the objects. A wave speed may be determined from a ratio of the change in fluid velocity at the longitudinal position as a function of time and the change in a logarithmic function of the conduit diameter as a function of time. A measure of wave intensity may be determined as a function of change in determined conduit diameter and corresponding change in fluid velocity.

A method of determining a measure of wave speed or intensity in a fluid conduit uses ultrasound measurements to determine the conduit diameter and fluid velocity in a volume element, each as a function of time, and each at a same longitudinal position of the conduit. The ultrasound measurement to determine fluid velocity is effected by tracking objects within the fluid flow in successive frames sampling the volume element, and obtaining displacement vectors for the objects. A wave speed may be determined from a ratio of the change in fluid velocity at the longitudinal position as a function of time and the change in a logarithmic function of the conduit diameter as a function of time. A measure of wave intensity may be determined as a function of change in determined conduit diameter and corresponding change in fluid velocity.

A method of determining a measure of wave speed or intensity in a fluid conduit uses ultrasound measurements to determine the conduit diameter and fluid velocity in a volume element, each as a function of time, and each at a same longitudinal position of the conduit. The ultrasound measurement to determine fluid velocity is effected by tracking objects within the fluid flow in successive frames sampling the volume element, and obtaining displacement vectors for the objects. A wave speed may be determined from a ratio of the change in fluid velocity at the longitudinal position as a function of time and the change in a logarithmic function of the conduit diameter as a function of time. A measure of wave intensity may be determined as a function of change in determined conduit diameter and corresponding change in fluid velocity.

A system and method for monitoring fluid flow in a downhole reservoir, characterized by at least one energy source (1), which simultaneously sends two or more utility pulses. The pulse can be a fast propagating and flow-independent acoustic pulse, a somewhat slower propagating and flow-dependent pressure pulse, a slow propagating heat pulse or a slow-propagating tracer pulse. The energy sources are connected via said pulses, without cable, and at least an upper heat source (1′) is connected to equipment on the surface via a cable (4).

A system and method for monitoring fluid flow in a downhole reservoir, characterized by at least one energy source (1), which simultaneously sends two or more utility pulses. The pulse can be a fast propagating and flow-independent acoustic pulse, a somewhat slower propagating and flow-dependent pressure pulse, a slow propagating heat pulse or a slow-propagating tracer pulse. The energy sources are connected via said pulses, without cable, and at least an upper heat source (1′) is connected to equipment on the surface via a cable (4).

Apparatus is provided having an acoustic-based air probe with an acoustic source configured to provide an acoustic signal into a mixture of concrete; and an acoustic receiver configured to be substantially co-planar with the acoustic source, to respond to the acoustic signal, and to provide signaling containing information about the acoustic signal injected into the mixture of concrete.