利用液晶顯像技術量測斜壓渦漩之速度及溫度場

Abstract

本文以水工實驗模擬渦漩具背景渦度且存在溫度效應影響下的行為表現，利用旋轉水槽底部架設具有溫度效應區的斜板模擬緯度效應及溫度來源，使渦漩通過此區域，分別以染料施放法定性觀察其路徑，以雷射水平切頁顯影法定量觀察其速度場，及液晶顯像技術(PIV/T)量測其垂直方向的速度及溫度場。 歸納自實驗結果，溫度效應對於渦漩路徑影響為冷渦漩較常溫渦漩偏北，而熱渦漩較常溫渦漩偏南。 另外，本實驗使用可隨溫度變化改變其反射波長的液晶感溫粒子(Thermochromic liquid crystal)為追蹤粒子，以水為工作流體，利用液晶顯像技術以全域且非侵入式的方式量測渦漩進入溫度效應區前、中、後三區域的速度溫度場，以觀察分析溫度效應對於渦漩垂直方向流場的影響。

The objective of this paper is to investigate the phenomenon of vortex under thermal effect and background vorticity, especially the path and intensity of vortex passing through hot/cold zone. The generations of vortices at relative locations or latitudes are carefully conducted by sinking methods. The vortex is moved from deep water to shallow water because of the inclined bottom plate with hot/cold zone. The vortex path is observed by dye-induced method qualitatively. Moreover, the velocity, vorticity, and temperature of the fluid field are obtained by Particle Tracking velocimtry (PTV) and Particle Image Velocimetry/ Thermometry (PIV/T) quantitatively. By conclusion of series of experiments, the path of the cold vortex which passes through cold zone is northerner than that through ambient-temperature zone. Moreover, the path of the vortex passing through ambient-temperature zone is northerner than that through warm zone.