Field multipath digital earth-surface shear stress dynamic monitor

Abstract

The invention relates to a field multipath digital earth-surface shear stress dynamic monitor which is characterized in that each earth surface shear head is connected with a main press nozzle, a main gas outlet nozzle, a subsidiary press nozzle and a subsidiary gas outlet nozzle, and is communicated with a micropressure difference transmitter through a respective silica gel hosepipe and a negative-pressure gas inlet nozzle and a positive-pressure gas inlet nozzle; and an output electrical signal of each micropressure difference transmitter passes through a negative signal line, a positive signal line, a transmitter power line negative end and a transmitter power line positive end to be welded with an aviation plug seat. An apparatus chassis is provided with a multipath plug seat; a bridge stabilized voltage supply, a multipath conversion circuit and a 485-to-USB head are arranged in the chassis; the bridge stabilized voltage supply is connected with the multipath conversion circuit; the 485-to-USB head is connected with a computer acquisition data storage and a computer data display through a 485 data line; and a solar cell panel is connected with a hermetically sealed lithium battery which powering the micropressure difference transmitter. The monitor provided by the invention has advantages of simple structure, multiple paths, accurate measurement, small volume and high intelligence, and can be suitable for field site and indoor wind tunnel test earth-surface smooth variation observation.

Description

[0001] technical field [0002] The invention relates to an instrument for dynamic monitoring of field multi-channel digital surface shear stress. [0003] Background technique [0004] From a microscopic point of view, the shear effect (shear stress) of wind on the sandy surface directly affects the critical starting velocity, jump height and jump length of sand particles, thus affecting the wind-sand flow structure of the wind-sand boundary layer, and The formation process of sand ripples; From a macro perspective, wind shear directly affects the formation and evolution process and spatial distribution pattern of aeolian landforms in arid areas. Recently, many studies on sand dune dynamics at home and abroad have focused on inferring the movement characteristics of sand grains and the transport process of wind-sand flow through the response of wind speed profiles, or directly measuring the influence of near-surface wind speed on sand transport. However, in previous studi...

AI Technical Summary

Problems solved by technology

However, the biggest disadvantage of this instrument is that it interferes a lot with the wind field and wind-sand flow structure, and secondly, it cannot measure the air velocity close to the ground surface (<5mm)

Because the PIV system uses the principle of laser velocity measurement, the ground surface is very reflective, so the minimum ground distance it can measure is more than 2~5mm, and it is also impossible to measure the characteristics of the airflow close to the ground surface, which limits its use. Application in the measurement of surface airflow characteristics, so up to now it is impossible to fully grasp the characteristics of surface airflow when the wind and sand flow passes by

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