- 期刊
定型渠道應用表面流速法推估垂向平均流速及流速特性之研究
Experimental Study on the Application of the Estimation of Average Vertical Flow Velocity and Characteristics of Flow Velocity By Using Surface Flow Velocity Method in Prismatic Channels
摘要
非接觸式觀測方法為新穎的流速測定法，手持式雷達波流速儀（RSV）為表面流速觀測的主要應用設備，應用本法需事先進行垂向平均流速推估式之建立；本研究於2017～2019年透過現地試驗方式，分別應用RSV及聲波都卜勒剖面流速儀（ADP）量測表面流速與垂向平均流速，針對臺中灌區定型渠道分析及探討表面流速與垂向平均流速間之關係並進而建立修正公式，成果顯示以灌溉為用途的定型渠道圳路應用RSV測定流速時，可簡易應用單一修正係數K_(AV)為1.099；若根據渠道規模進行區分，幹線系統之修正係數K_(AV)為1.040、支線系統為1.168、分線系統為1.112、小給水路之修正係數K_(AV)為1.075；應用表面流速測定值修正後之流速與應用ADP測定之垂向流速相較之偏差可分別縮小至2.18%、0.32%、7.36%、4.07%。其次，本研究以表面流速與垂向流速比值K_U評估其與渠道斷面深寬比（d/W）之關聯性，結果顯示K_U與（d/W）成反比，K_U隨著（d/W）遞減程度的數學式為K_U=-0.172（d/W）+0.904。
並列摘要
The non-contact observation is a novel method for measuring flow velocity. Radar surface velocimeter (RSV) is the main application equipment for surface flow velocity observation. The application of this method requires the establishment of the average vertical flow velocity estimation formula in advance. This research conducted on-site test methods by using RSV and Acoustic Doppler Velocimeter (ADP) to measure surface flow velocity and vertical average flow velocity, respectively, and further to analyze the relationship between surface flow velocity and the average vertical flow velocity to establish a correction formula in Taichung during 2017-2019. The results show that a single correction coefficient K_(AV) can be easily applied to 1.099 by using RSV to measure the flow velocity in prismatic channels. Moreover, the correction factor K_(AV) for the main, the secondary, the branch, and the supply canals are 1.040, 1.168, 1.112, and 1.075 respectively. Comparing with the vertical flow velocity of ADP, the deviation of the modified surface flow velocity can be reduced to 2.18 %, 0.32 %, 7.36 %, 4.07 %, respectively. Secondly, the ratio of surface velocity to vertical velocity, K_U, was used to evaluate its correlation with channel section aspect ratio (d/W). The results show that K_U is inversely proportional to (d/W), and the mathematical formula of K_U decreasing with (d/W) is K_U = -0.172(d/W)+0.904.