利用實測表面流速推估高流量之研究

Estimation of High Discharge Using Measured Surface Velocity

10.29417/JCSWC.201103_42(1).0003

林穎志(Ying-Chih Lin)；朱木壽(Mu-Shou Chu)；詹勳全(Hsun-Chuan Chan)；高昇敬(Shen-Ching Kao)；呂珍謀(Jan-Mou Leu)

流量 ； 表面流速 ； 非接觸量測 ； discharge ； surface velocity ； non-contact measurement

中華水土保持學報

42卷1期（2011 / 03 / 01）

23 - 36

繁體中文

為能安全即時地獲取高流量流況之實測流量，近年來已陸續發展數種不需接觸水體即能測得水流表面流速之儀器，並逐漸應用於實務量測作業。本文以連續波微波雷達表面流速儀搭配水位計等非接觸式儀器設計建構全自動量測系統，其所測得渠道高流量期間表面流速及水位之短期距資料，則由垂直剖面速度分布經驗公式轉換為平均流速進而推得流量。藉由渠道試驗，以入流量為參考基準，探討非接觸式量測系統所測得高流量資料之準確性，研究過程採用表面流速儀分別以30°、45°及60°等三種俯角測得表面流速，流量推估結果與入流量比較之平均差異分別為34.9%、14.4%及-0.6%。另外，現場資料驗證採曾文溪新中水位流量站所設之非接觸式量測系統，以系統設置期間測得之颱洪資料，顯示量測系統可全天候地測得洪水歷程短期距之水位及表面流速變化情形，由分析資料則可呈現出洪水期間之遲滯效應，此為傳統實測作業不易獲取之資訊。

Surface velocity distribution measured by non-contact techniques is currently used to obtain the flow information during floods. A non-contact measurement system, consisted of a continuous wave microwave Doppler radar and an ultrasonic sensor gauge, is established to measure stages and surface velocities of floods. This system obtains flood discharge without operation of human power and invasive measurement. In the laboratory flume, the non-contact measurement system is used to measure the inflow discharge. The continuous wave microwave radar is installed in three depression angles of 30°, 45° and 60°. The discrepancies between measured discharge and the inflow discharge are 34.9%, 14.4% and -0.6%, respectively. The field data of the non-contact measurement system established in Zengwen River indicates the system successfully captures continuous flood discharge during typhoons. The measured surface velocities and water levels both present the effect of hysteresis which is difficult to capture by the conventional flow measurement.