Application of Composite Grid Approach in Computing Flow around Ship with Appendage

Abstract

In order to deal with complex geometry, a composite grid method is developed and incorporated with the USDDC RANS solver. In the composite grid approach, the numerical grids of different zones can overlap with each other in the computational domain. More flexibility and ease in generating numerical grids can be obtained. Grid skewness can be better improved, and therefore the numerical diffusion can be also reduced. Two examples are demonstrated here to show the advantage of applying overlapping grids. At first, the numerical computation of flow around a twin-skeg bulk carrier is shown. Better numerical prediction of propeller wake by a composite grid is obviously observed compared to the one by a traditional block-structured grid. The second one shows the numerical prediction of wake improvement of a container ship by installing a pair of vortex generator on ship hull near stem. Again the numerical results agree well with wind tunnel measurements. The composite grid approach is proven to be an effective means to compute flow for complex geometry with required engineering accuracy.