- 學位論文
Numerical Study on Scale Effect of Form Factor
Numerical Study on Scale Effect of Form Factor
並列摘要
In the present thesis, the computational fluid dynamics method is applied to study the scale effect problem of the form factor. In this method, the turbulent flow around ship hull is analyzed by solving the Reynolds-averaged Navier-Stoke equation using the finite volume method. The space parallelism and a PC-cluster with 16 nodes are employed to speed up the computations. First, the applied method is verified at model-scale by comparing the calculated results with the measured data from the model tests. The grid dependency problem is studied by refining the grids systematically. It improves the reliability of the numerical approach and makes that the present method has the ability to predict the ship flow. The prediction is verified using the model test which is performed subsequently. Moreover, the full-scale ship flow is also computed and compared to the model-scale ship flow in this thesis. The resistance predictions at full-scale are indirectly verified through the qualitative comparisons of the important flow properties at different scales. In the last part of the present thesis, the resistance of several kinds of surface ship and sub-body are computed at different Reynolds numbers. By comparing the calculated results in this thesis, the scale effect problems of the form factor are discussed. Reviewing all calculated results, a unique trend among all hull forms is observed in the specific range of Reynolds number. As Reynolds number increases, the ratio of the pressure term to the total resistance increases, and the form factor also increases slightly.