自作転倒升型流量計を含めた安価な流量計の樹幹流観測における精度検証  [in Japanese] Accuracy of Low-cost Flow Meters for Stemflow Observation Including Handmade Tipping Buckets Flow Meter  [in Japanese]

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Abstract

<p> 野外利用可能な安価な流量計の精度検証を行った.検証には自作転倒升型流量計,容積式流量計,水道メーターを選択した.室内検定から,自作転倒升型流量計は2秒間で1転倒する程度までの流入流量では,市販型と同様に1 次式での検定直線を引くことが可能であることが分かった.また,転倒升の転倒時間と升貯留量の関係が検定曲線を特徴づけていることが分かった.樹幹流を対象とした野外試験では,転倒升型流量計の測定誤差は5 %以内に収まった.また,容積式流量計および水道メーターは小流量での測定限界が存在するため,滴下程度の流量を測定するためには流量変換装置が必要であること,水道メーターは流量計出口側に2 mに相当する水圧をかけることが必要であることが分かった.容積式流量計は流体内の不純物に対して誤差を生じやすく,不純物の除去に特別な配慮が必要である.総合的に判断すると,野外における安価な流量計としては自作転倒升型流量計が多くの点で優れていることが分かった.</p>

<p> This study examined the accuracy of low-cost flow meters used for field observations. We specifically examined handmade tipping buckets flow meters, volumetric flow meters, and tap water meters. For inflow rates lower than one tip per 2 s, laboratory tests demonstrated that handmade tipping buckets flow meters have the same calibration line among inflow flux and one tipping quantity as commercial ones. Calibration curve characteristics of tipping buckets flow meters were estimated from the tipping time and storage volume when tipping. Stemflow observation measurements in the field with handmade tipping buckets meters were within 5% error. Volumetric flow meters and tap water meters must be used to add some flow current exchange systems because they are unable to detect water flow at lower flux, such as when they are dropping. Moreover, tap water meters require 2 m water height pressure at the meter exit. Volumetric flow meters have shown large error in field experiments because they are vulnerable to fluid impurities. Some measures must therefore be used to remove impurities. We were able to judge comprehensively that handmade tipping buckets flow meters are superior in many respects as low-cost flow meters for field observations.</p>

Journal

  • JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES

    JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES 31(5), 380-392, 2018

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES

Codes

  • NII Article ID (NAID)
    130007497780
  • NII NACSIS-CAT ID (NCID)
    AN10088049
  • Text Lang
    JPN
  • ISSN
    0915-1389
  • NDL Article ID
    029259586
  • NDL Call No.
    Z15-619
  • Data Source
    NDL  J-STAGE 
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