What is described is a method for charactering an airflow, having the following steps: receiving acoustic signals generated by the airflow by means of a microphone array; extracting a characteristic information from the acoustic signals; determining an information on the airflow based on the characteristic information.

A fluid device includes: a flow path through which a fluid flows; and an ultrasonic element configured to transmit an ultrasonic wave to the fluid to generate a standing wave in the fluid in the flow path along a first direction orthogonal to a flowing direction of the fluid. The ultrasonic element includes a vibrator having a fluid contact surface that comes into contact with the fluid, and a piezoelectric element that is provided at the vibrator and that is configured to flexurally vibrate the vibrator in a normal direction of the fluid contact surface. When a thickness of the vibrator in the normal direction is t, a sound velocity of a medium of the fluid is C, an average sound velocity of a longitudinal wave transmitted in the vibrator is C′, a dimension of the flow path in the first direction is L, and a mode order of the standing wave is n, the following expression is satisfied.

[00001]$t<\frac{C^{\prime }}{C}\times \frac{L}{2n}$

Acoustic Doppler current Profile (ADP) data may be collected by floating vessels down a section of a river. The ADP data may be merged with LIDAR data or other image data. The data may be processed to determine river attributes, such as flow velocity for a specific river level (flow volume). River attributes may also include depth, water clarity, temperature, and/or other river attributes. Capture of ADP data at different river levels may be interpolated between measures to estimate river attributes at multiple river levels that are different from the river levels associated with the collected ADP data. The processed data may be used to assess drift of particles/objects through a section of the river and/or identify conforming habitat in the section of the river based at least in part on parameters of the habitat, among other possible uses of the processed data.

The disclosure relates to a reflection unit applied to an ultrasonic anemometer and used to reflect ultrasonic waves from a transmitter, wherein the reflected ultrasonic waves are received by a receiver. The reflection unit comprises a reflection plate and further comprises a mesh cover layer structure covering on the upper surface of the reflection plate. In an embodiment of the present disclosure, the mesh cover layer is provided on the reflection plate, so that the raindrops/water droplets falling on the reflection unit can be quickly scattered on the surface of the reflection unit, thereby eliminating the irregular shape and high liquid accumulation formed on the surface of the reflection unit, ensuring the accuracy of ultrasonic anemometer measurements in wind and rain conditions.

A method is provided for non-invasively determining properties of a multiphase flow which flows through an electrically conductive object. Using a single set-up having a plurality of EMAT transducers, at least one property of the multiphase flow is determined by means of at least one of a plurality of measurement methods. A device is also provided for non-invasively determining properties of a multiphase flow which flows through an electrically conductive object. At least four EMAT transducers are positionable upstream along a first object cross-section at or near the object wall and at least four EMAT transducers are positionable downstream along a second object cross-section at or near the object wall.

A system for measuring a rising velocity and a deformation of a bubble in a viscous fluid includes a sample cell configured to hold a viscous fluid, a variable-diameter syringe provided at a bottom of the sample cell and configured to generate a bubble in the viscous fluid, two ultrasonic transmitting and receiving transducers arranged at different heights of the sample cell and configured to transmit first ultrasonic signals to the viscous fluid and receive second ultrasonic signals reflected by the bubble, and a host computer configured to analyze time-domain information of the second ultrasonic signals received by the two ultrasonic transmitting and receiving transducers, calculate the rising velocity of the bubble, build a mathematical model about a bubble size and a reflected sound pressure, analyze frequency-domain information of the second ultrasonic signals received by the two ultrasonic transmitting and receiving transducers, and calculate the deformation of the bubble.

A flowmeter for measuring a flow of a fluid has a sensing element that has a pipeline for the fluid with a pipe wall, at least one phased array ultrasonic transducer unit, which can emit ultrasonic signals into different emission angles and can receive ultrasonic signals from different reception angles, a control and evaluation unit that is designed to control the ultrasonic transducer unit for emitting the ultrasonic signals along a measurement path and for evaluating the received ultrasonic signals and determining a flow using transit times of the ultrasonic signals. The sensing element has at least one reflector, which is designed to reflect the ultrasonic signals emitted by the ultrasonic transducer unit back to the same ultrasonic transducer unit. The ultrasonic signals pass through the measurement path from the ultrasonic transducer unit to the reflector and back to the ultrasonic transducer unit on at least partially different path sections.

A throughflow measurement system comprises a measurement body that has an inlet flange, an outlet flange and a fluid passage, wherein the fluid passage has a passage axis; an ultrasonic measurement apparatus integrated into the measurement body; and a flow conditioner arranged upstream of the ultrasonic measurement apparatus in the fluid passage. An arrangement of bores for fastening means is provided at the outlet flange, wherein an axially extending outlet fastening region of the measurement body is defined by the length of the bores. The ultrasonic measurement apparatus has at least one reflection measurement path that is spanned by a first ultrasonic transducer, a reflector and a second ultrasonic transducer and that extends in a measurement plane through the fluid passage such that the second ultrasonic transducer is arranged downstream of the first ultrasonic transducer. The second ultrasonic transducer disposed downstream is arranged in or projects into the outlet fastening region.

Systems and methods for enabling consistent smooth takeoffs and landings of vertical and/or short-runway takeoff and landing aircraft at sites with gusty conditions. The system includes a network of wind measurement stations deployed around the perimeter of a takeoff/landing site for spatio-temporally characterizing wind fluctuations (e.g., wind gusts) that enter a volume of airspace overlying the site, data processing means for deriving information about the fluctuations from the wind measurements, communication means for transmitting disturbance information to the aircraft, and a flight control system onboard the aircraft that is configured to use the disturbance information to control the aircraft in a manner that compensates for the fluctuations. The wind measurement units may include laser Doppler anemometers, sound detection and ranging systems or other devices capable of simultaneous spatially and temporally resolved wind measurements.

An object detection device that detects an object existing around a moving body moving on a road surface by transmitting and receiving ultrasonic waves, includes: a first acquisition unit configured to acquire reflection intensity information indicating an intensity of a reflected wave from the object; a first generation unit configured to generate object information indicating existence of a predetermined detection target when the reflected wave having an intensity exceeding a threshold value is received; an estimation unit configured to estimate a wind speed based on a road surface reflection intensity, which is an intensity of a reflected wave from the road surface; and a setting unit configured to change the threshold value according to the wind speed.