船模在拖航水槽進行阻力試驗為了減少尺度效應造成誤差，船模尺寸大多介於7~9m之間，然而水槽尺寸為有限寬度，因此阻力實驗受到槽壁效應影響。本文根據日本長崎大學之槽壁效應研究，分析拖航水槽之阻力試驗，將在小水槽與大水槽之阻力差值視為槽壁效應造成的阻力增加值，並比較不同速度時大小水槽之阻力差異再以理論迴歸出槽壁校正係數，得到無槽壁效應之阻力值。
本研究選用某貨櫃輪與油輪模型為研究對象，利用商用計算流體力學軟體ANSYS FLUENT 進行數值模擬，分別與HSVA水槽實驗報告與Ocean Engineering論文之實驗結果比對，以驗證計算結果可信度。數值計算前先進行網格獨立性分析，確保所使用的網格數量適當，減少網格計算時間；接著，以等比例縮放船模尺寸進行模擬求得模型總阻力，目的為探討船舯剖面面積與水槽斷面積之相對面積比(m)、佛勞得數(Froude Number)兩因子中，槽壁效應對船體模型阻力之影響，並比較胖瘦船型之槽壁影響。結果發現，相同速度下，因大船模受槽壁效應影響，剩餘阻力係數(Cr)較大。油輪雖航行速度慢，但船模寬與吃水皆大於貨櫃輪，槽壁效應影響明顯。由計算結果推測，影響槽壁效應因子包括速度(Fr)、船舯剖面與水槽剖面相對面積比(m)、船寬與水槽寬比(b/B)、船吃水與水深(d/D)等等。
本文將大量數據無因次化後，以相對面積比、佛勞得數、寬度比、深度比、方塊係數為自變數，使用統計軟體SPSS進行線性複迴歸分析，分別提出對貨櫃輪與油輪之校正公式。接著，希望迴歸出一條適用所有船隻的校正公式，結合貨櫃輪與油輪之阻力數據重新迴歸，求得適用校正兩種船隻之槽壁校正通式，提供成大水槽對於水面船隻阻力之良好校正，以期未來能作為實驗之阻力校正的參考指標。最後，參考ITTC經驗公式，為了方便實驗進行，阻力校正公式多以修正台車速度為主，因此本研究再次修正阻力校正係數，改以校正台車速度。
本文以一總阻力校正公式與一速度校正公式為結論，提供往後成大拖航水槽執行船體阻力試驗時，修正槽壁效應的參考指標。

The main goal of this study is to propose a correction formula to revise the blockage effect for ship drag by CFD method. The final objective is to develop one resistance corrected formula and one velocity corrected formula with respect to the section ratio, Froude number, width ratio, depth ratio and Cb for correcting the blockage effect of NCKU towing tank.

It is quite common to apply model test in towing tank to acquire ship resistance and hydrodynamic coefficient in model scale; however, model test would be affected by blockage effect in a restricted tank. Blockage effect is a widely known issue in the field of naval architecture. To realize the principle of blockage effect of ship drag in NCKU towing tank, the present study carried out numerical simulation for container and KVLCC2 tanker by ANSYS FLUENT. Compare various types of correction factors, such as section ratio, Froude number, width ratio, depth ratio and Cb to simulate different condition effected by blockage effect. With the above five blockage correctors, the present study utilizes statistical software SPSS to regress analysis. At the end, two correction formulas are proposed to modify blockage effect for NCKU towing tank.

On the basis of the research, we find the resistance correction formula proposed in this paper has valid correction result at the relative section ratio between 0.006 and 0.035, and the maximum error is 3%.The other formula, velocity correction formula, also has valid correction result at section ratio between 0.006 and 0.035.Morever, in this case, when Froude number between 0.13 to 0.24 and section ratio less than 0.006, towing tank can be seen as no blockage effect.

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