臺灣地區田間人工降雨機之研製、操作、率定及分析

Design, Fabrication, Operation, Calibration and Analysis of a Field-Scale Rainfall Simulator in Taiwan

范正成(Jen-Chen Fan) ； 吳明峰(Min-Fon Wu)

《中華水土保持學報》 27卷1期 (1996/03) Pp. 1-13

https://doi.org/10.29417/JCSWC.199603_27(1).0001

摘要

利用自然降雨來研究土壤沖蝕，相當耗費時間及人力，而且不能控制降雨的情況。如果使用人工降雨機，就可以避免這些缺點。雖然在臺灣已經有針對人工降雨機之研究，但是可以在田間操作且功能齊全，性能良好之人工降雨機尚屬闕如。本研究成功的研究完成改良式Fan and Lovell（1987）型人工降雨機。改良的項目包括長槽機體（troughs），噴嘴數量，長槽機體傾斜角度調整器，擺動機制之軸承，供水系統之分水閥門，使得此人工降雨機在田間之操作性更佳，且可適用在高達100%之陡坡上。本研究也完成了改良式Fan and Lovell（1987）型人工降雨機之率定及分析。率定及分析立項目包括降雨強度，雨滴粒徑，雨滴落速及單位降雨動能。其中，將人工降雨機相鄰兩具長槽機體中心距由153 cm減為138 cm後，降雨強度之空間均勻係數由不到88%提升至93.7%。各項目率定其分析之結果都相當令人滿意。

關鍵字

人工降雨機 ； 率定 ； 陡坡 ； 土壤沖蝕 ； 降雨強度 ； 雨滴粒徑 ； 雨滴落速 ； 降雨動能

並列摘要

It is rather time consuming and difficult to control the rainfall condition to study soil erosion using natural rainfall. If rainfall simulators are applied, these disadvantages can be avoided. In Taiwan, although there were some studies on rainfall simulators in the past, yet up to now there was still no rainfall simulator with good functions and quality, which can be used in the field. In this study, a rainfall simulator was successfully designed and constructed by modifying the rainfall simulator developed by Fan and Lovell (1987). The modifications included troughs, quantity of nozzles, adjusting devices for the steepnesses of the troughs, bearing connections between oscillating nozzles and the water supply system, and a manifold in the water supply system. After modified, the rainfall simulator can be operated more satisfactorily in the field with slope steepnesses ranging from 0 to 100%. The rainfall simulator developed in this study was also calibrated and analyzed. The items consist of rainfall intensity, raindrop size, raindrop fall velocity and kinetic energy of unit rainfall. In the calibration, after the distance between the two adjacent troughs were reduced from 153 to 138 cm, the spatial uniformity coefficient was increased from less than 88 to 93.7% . All the results of the calibrated and analyzed items were rather satisfactory.

並列關鍵字

Rainfall Simulator ； Calibration ； Steep Slope ； Soil Erosion. Rainfall Intensity ； Raindrop Size. Raindrop Fall Velocity ； Kinetic Energy of Rainfall