Abstract: A stationary system is for measuring the surface velocity of a fluid flowing in a river, an open channel or an underground pipe. The system includes a non-invasive device measuring the surface velocity of the fluid, and a wind speed and direction measuring device to validate and/or to correct the measurements taken by the non-invasive device in order to take into account the effect of the wind on the surface velocity of the fluid. A method for validates and/or corrects the measurements carried out by the non-invasive device as a function of the wind speed and direction.

Abstract: A sensor assembly is for measuring average velocity of a fluid flowing in a closed conduit or in an open channel. The sensor assembly is adapted to measure average velocity though closed conduits of different sizes or through open channels with different fluid levels. The sensor assembly includes a housing extending across an inside of the closed conduit or to extend vertically in the section of the open channel. The housing includes pairs of electrodes and at least one associated electromagnet for measuring the velocity distribution in the closed conduit or in the open channel. An isolator allows isolation from the pairs of electrodes or from signals of the pairs of electrodes that are not in contact with the fluid flow to be measured. The isolator is configured to be adapted depending on water level in the open channel or size of the closed conduit.

Abstract: A non-invasive microwave measuring device (01) is for calculating the flow rate of a fluid. The device (01) includes a non-invasive microwave fluid velocity measuring device (03) having a patch antenna or horn antenna to generate a microwave signal (14) that is transmitted at a specific elevation angle ? towards the fluid surface (16) and to receive the reflected microwave signal (15) from the fluid surface (16) with a doppler shift frequency. The measuring device (03) is suspended from a drone (02) by a suspension system (04). The suspension system (04) eliminates vibration noise generated by the drone (02). At least one vibration sensor eliminates false velocity readings. At least one angle sensor compensates for Pitch, Roll and Yaw from the drone (02) that influence the fluid surface velocity measurement.

Abstract: A method measures surface velocity of a fluid having a free surface flowing through a pipe or a channel. A microwave beam is sent by patch antenna including an emitting patch area and receiving patch areas parallel to the emitting patch area. Microwave signals reflected by the moving fluid free surface are received on the receiving patch areas separated by a predetermined distance. The patch antennae are either in horizontal or vertical planes parallel to the average fluid velocity. For each microwave signal received, a phase shift between microwave signals received by different patch areas is determined to calculate azimuth angles and azimuth position of reflectors on the fluid surface or to calculate the elevation angle corresponding to each signal received. Based on Doppler frequency shifts between the sent and received microwaves and corresponding phase shifts, lateral and/or longitudinal distribution of the surface velocity of the fluid is calculated.

Abstract: The invention relates to a device (7) for measuring the surface velocity of a fluid (10) flowing in a confined space such as through a pipe or a channel (12), said device (7) comprising a patch antenna (1) with a transmitting area (1a) generating a microwave signal and a receiving area (1b) receiving the microwave signal reflected on the surface of the fluid (10), the device (7) being wherein it comprises an electrically conductive tube (8), called reflector tube, with at least the transmitting area (1a) of the patch antenna (1) mounted at one end (8a) of the reflector tube (8) to reduce the side lobes of the generated microwave signal. The invention also relates to the non-invasive method for measuring the surface velocity of the fluid using said device (7).

Abstract: A method calculates mean speed of a fluid flowing in an open channel or a partially filled duct. Fluid having a free surface of width L1 extending between walls of the channel or duct includes local speed measurements at the surface of the fluid over a zone of width L2, the set of local measurements generating a spectrum of discrete data expressed in a temporal domain. The spectrum of discrete data is converted into a spectrum of data expressed in a frequency domain via a Fourier transform. A Gaussian curve is fitted to the spectrum and the mean ? and the standard deviation ? of the Gaussian curve are calculated. L2 and ? enable calculating the distribution of speeds over L2. The ratio L2/L1 is calculated and the mean speed of the fluid within the channel or duct is determined based on the Gaussian curve and the ratio L2/L1.

Abstract: A method calculates mean speed of a fluid flowing in an open channel or a partially filled duct. Fluid having a free surface of width L1 extending between walls of the channel or duct includes local speed measurements at the surface of the fluid over a zone of width L2, the set of local measurements generating a spectrum of discrete data expressed in a temporal domain. The spectrum of discrete data is converted into a spectrum of data expressed in a frequency domain via a Fourier transform. A Gaussian curve is fitted to the spectrum and the mean ? and the standard deviation ? of the Gaussian curve are calculated. L2 and ? enable calculating the distribution of speeds over L2. The ratio L2/L1 is calculated and the mean speed of the fluid within the channel or duct is determined based on the Gaussian curve and the ratio L2/L1.

Abstract: A method measures a hybrid flow rate (Q) of a fluid using simultaneously at least two measuring technologies and a reference measurement, the method includes a hybrid value, wherein the measurements of the at least two measuring technologies are combined according to a given rule to get the hybrid value by performing a linear or non-linear interpolation within a given interval of the reference measurement.

Abstract: A method measures a hybrid flow rate (Q) of a fluid using simultaneously at least two measuring technologies and a reference measurement, the method includes a hybrid value, wherein the measurements of the at least two measuring technologies are combined according to a given rule to get the hybrid value by performing a linear or non-linear interpolation within a given interval of the reference measurement.