本文將引用虛擬溫度粒子概念，以Lagrangian方式並結合隨機走步式之渦流法來模擬探討二維平面熱噴流的動力特性，並分成有無熱流耦合效應之強制與起始熱噴流兩部分探討。本文第一部分將模擬探討無熱流耦合之強制熱噴流空間演進特性，研究在不同之雷諾數與普朗特數下，探討在紊流中之流場與溫度場特性，發現其經由速度及溫度空間演進特性模擬結果，將與文獻之實驗結果相符合，顯示此數值結果具一定之可靠性。由數值結果中不僅得到清晰熱量與動量交換之交界面，並得到流場與溫度場之良好高斯相似性分佈以及與實驗一致性的半幅寬演進發展，以及中心速度與溫度與溫度x−1/ 2 收斂衰減趨勢等特性。本文第二部分為模擬探討具有熱流耦合效應之起始熱噴流發展特性，將溫度場中產生具有密度差的浮力效應引入探討，以觀察起始熱噴流之演進發展與理查森數對於熱流場演進之影響。由數值結果可知，隨著理查森數的增加，可發現流場速度有明顯加速的現象，並且可以觀察出流場的原始點渦流將隨著熱場所產生的點渦流所驅動發展之。

A Lagrangian approach involved the virtual temperature particles is presented in this study. In addition, the dynamic characteristics of two-dimensional planar thermal jet are simulated and investigated by this approach combining with the vortex method of random walk. This research is fully separated into forced thermal jet without heat-flow coupling and starting thermal jet with heat-flow coupling as follows. In the first part of present study, the turbulent investigations on the spatial evolution characteristics of the forced thermal jet with different Reynolds numbers and Prandtl numbers are studied. The numerical results are not only reasonable but also get excellent agreement with the experimental data of available literatures. The clear interface and diffusive transportations of momentum and heat energy are observed. The agreeable self-similar relations with Gaussian distribution and consistent development with experimental data of the velocity and temperature half-widths are obtained as well. Besides, the decay properties of the velocity and temperature from the jet centerline are valid. In the second part of this study, the investigations on the development properties of the starting thermal jet with different Richardson numbers are studied. The numerical results show that the acceleration in flow field obviously as the Richardson numbers increase. It is also observed that the original vortex of flow field is driven by the generated vortex of thermal field.

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