An investigation of superstructure length on bi-stable ship wake flow

Artikel i vetenskaplig tidskrift, 2024

The variation in the geometry of a ship model has the potential to eliminate the flow asymmetry in ship wake and improve its aerodynamic performance. This study investigates the impact of the length of superstructure on the wake flow bi-stability of the ship model using IDDES at Re = 8 × 104. Also, this article studied the effect of ship's funnel structure using two models, with and without funnel, on the wake flow asymmetry, providing smooth transition into the study of the length of superstructure. The result indicates that when the funnel is removed, the length of flow reattachment after separation at the hanger increases for the top step and decreases for the second step for the case with no funnel. The asymmetric flow at wake persists, however, the configuration is different, showing difference in flow state. When the length of the superstructure is reduced, the turbulence at the wake increases, the size of recirculation bubble at the flight deck and behind the stern reduces and the overall pressure area decreases significantly. Behind the stern, all three cases indicate an asymmetrical flow, however, compared to Case 1, the asymmetry at the flight deck in Case 2 is weak, while a symmetrical flow is achieved with Case 3. Consequently, this research proposes a novel approach to improving wake flow and ensure safe aircraft take-off and landing operations on the ship deck.