二方程紊流模型於船舶流場計算之比較

Comparison of Two-Equation Turbulence Models in Ship Flow Computation

Nowadays, two-equation models are the most widely-used turbulence modeling method in ship flow computations. In this paper, three two-equation models, including the standard k-ε model, the Menter's baseline k-ω model, and the Menter's shear stress transport k-ω model, are employed to calculate steady ship flow. The calculated results are compared with the measured data. The influence of Turbulence modeling on some important flow properties, such as the flat-plate resistance and the propeller wake, are investigated. Furthermore, the CFD computations are performed at different Reynolds numbers and different grid spacing (y'). The influence of the y' is discussed. According to the CFD results, the Menter's baseline k-ω model gives the best prediction on the friction resistance. The Menter's shear stress transport k-ω model is superior in the wake prediction. 二方程紊流模型是現今船舶紊流場計算所最常使用的紊流模型，本文將標準k-ε模型、Menter基準k-ω模型、Menter剪力傳輸k-ω模型等三種二方程紊流模型，用於船舶穩態紊流廠的計算上，並且將計算結果與實驗量測結果比對。藉此，討論紊流模型對於重要流場特性計算結果的影響，包含了平板摩擦阻力與螺槳跡流。此外，本文還針對不同的雷諾數與不同的y'進行計算，以討論y'對於計算結果的影響。從本文的計算結果中發現，採用Menter基準k-ω模型可以獲得最好的平板摩擦阻力，至於Menter剪力傳輸k-ω模型則在螺槳跡流方面較為信奉優異。