Sailing at snorkel depth is a necessary but dangerous operating scenario for submarines. The main and straightforward reason is that such an operating condition represents a time of possible vulnerability of the vessel. From a design perspective this condition affects the so-called indiscretion rate, that is exactly the ratio between this time of greater vulnerability and the total operating...
Considered from the hydrodynamic perspective, submarines bring many interesting challenges that need to be properly addressed to provide precise information about their performance. Such hydrodynamic performance must be evaluated at least in two main operating conditions, namely when the vessel is deeply submerged and when it sails at snorkel depth. There are relevant differences both in terms...
Cavitation is a highly destructive phenomenon that significantly disrupts the performance of propellers and control surfaces in the maritime industry. Hence, the prediction of forces developed during cavitation, through various numerical techniques, is imperative for the design and operation of maritime vessels.
Since RANS turbulence models have proven to be the most computationally viable...
The interaction of the free surface with either lifting and non lifting, submerged, bodies moving beneath it is of primary interest in naval architecture. Indeed, there are many examples of possible applications such as rudders, stabilizer fins, hydrofoils among the others. The hydrodynamic problem of a submerged lifting body moving close to a free surface presents several complexities that...
This paper presents the investigation of a Pre-Swirl Stator (PSS) possible benefits on the ship powering system. Analysis of the PSS thrust augmentation is performed using the CFD simulations since the effects of turbulence and viscosity are important in the vicinity of the propeller. Direct propeller modelling is employed with the rotative region and propeller geometry present in the fluid...
