卡艾瑋臺灣大學：土木工程學研究所柯文韜Ke, Wun-TaoWun-TaoKe2007-11-252018-07-092007-11-252018-07-092005http://ntur.lib.ntu.edu.tw//handle/246246/50355本論文以實驗和數值計算的方式，來模擬河流沖積三角洲。以點源供沙的方式，觀察三角洲在下游堅硬底床上發展的過程。供應水流流量的方式是以急速薄層流流入楔型的靜止水槽。在三角洲逐漸發展的過程中，實驗設備的構造能確保沙子堆積的外部邊界可以自由發展。實驗觀察到的三角洲，為一高度二維蹼狀發展且鏡面對稱的構造。在實驗的過程中，沙子堆積的情形以雷射線配合攝影機進行測量。從拍攝得到的影像，可以捕捉到水面上、下的三角洲的地。經過一維解析解和實驗結果檢定的一維數值計算發展出來的二維數值模擬計算，可以用此方法得到二維沖積三角洲的模擬結果。The present thesis is devoted to the modeling of fluvial deltas, using both experimental and computational means. Attention is focused on idealized deltas developing over a rigid basement, downstream of a point source of sand. The water is supplied as a wide sheet of rapidly flowing water plunging into a wedge of standing water. This configuration ensures that the outer boundary of the sand deposit evolves freely over its entire perimeter during the gradual build-up of the delta. The observed deltas are highly two-dimensional in planform, adopting palmated structures which retain throughout their evolution a high degree of mirror symmetry. The delta deposit is surveyed during experiments by video imaging of a scanned laser sheet. Images are acquired above and below the standing water surface to capture both the topset and foreset topography. Two-dimensional shallow flow computations are performed to simulate the delta formation, using methods which are first validated against available one-dimensional analytical and experimental results.摘要 I Abstract II Contents III Table List VI Figure List VII 1. Introduction 1.1 2. Experimental set-up and measurement method 2.1 2.1. Experimental set-up 2.2 2.2. Laser-scan technique 2.5 2.2.1 Laser equipment set-up 2.5 2.2.2 Laser projective geometry 2.6 2.2.3 Calibration target 2.8 2.3. Ripple mark validation tests 2.10 3. Experimental observations and measurements 3.1 3.1. Observations 3.2 3.2. Topography measurements 3.6 3.3. Discussion 2.14 4. One-dimensional computations 4.1 4.1 Governing equations 4.2 4.2 Numerical scheme 4.3 4.2.1 Flow operator 4.3 4.2.1.1 Finite volume method 4.3 4.2.1.2 Eigenvalues 4.5 4.2.1.3 Stability condition 4.6 4.2.1.4 Nujić scheme for shallow flow over variable topography 4.6 4.2.1.5 Convected component 4.8 4.2.1.6 Hyperbolic operator 4.8 4.2.2 Source operator 4.9 4.2.3 Avalanche operator 4.11 4.3 Results and comparison 4.12 4.3.1 The dam break problem of the two-layer with layers having the same velocity without erosion and deposition 4.12 4.3.2 Comparison with experimental and analytical results for 1D delta 4.15 5. Two-dimensional computations 5.1 5.1 Governing equations 5.2 5.2 Numerical scheme 5.3 5.2.1 Operator splitting 5.3 5.2.2 x-operator 5.4 5.2.3 y-operator 5.5 5.2.4 Source operator 5.6 5.2.5 Avalanche operator 5.6 5.3 Results and comparison 5.8 5.4 Discussion 5.15 6. Conclusion 6.1 Appendix A: Derivation of avalanche operator equations A.1 References24689480 bytesapplication/pdfen-US淺水方程式三角洲shallow flowdeltathesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/50355/1/ntu-94-R92521302-1.pdf