Sovereign Submarine Research Capability for Near Free-surface Hydrodynamics

Submarines are required to operate at periscope depth due to operational requirements such as snorting, Special Forces operations and surveillance. The hydrodynamic behaviour when operating near the free-surface can be significantly different to when operating in deep water due to vehicle/free-surface interactions. These interactions have a direct impact on a submarine’s manoeuvring performance, depth keeping ability and safety. Submarines are typically designed and optimised to operate in the deeply submerged condition. Thus, the knowledge base for the periscope depth condition is somewhat limited. The ability to operate at effectively and safely periscope depth will improve the submarine’s mission performance.

This paper provides an overview of a collaboration project between the Defence Science and Technology Group (DSTG) and the Australian Maritime College (AMC) to develop sovereign capability to evaluate the hydrodynamic characteristics of submarines and its associated systems when operating near the free-surface. This includes the development of state-of-the-art experimental facilities and numerical tools to evaluate the performance of submarines operating near the free-surface. This paper describes computational fluid dynamics simulations to predict the hydrodynamic characteristics of the platform when operating near the surface in calm seas, which are validated against data from model scale experiments performed in the AMC Towing Tank. The results also provide input into the manoeuvring simulations to predict the behaviour of the submarine under varying configurations and conditions. This will provide guidance on the ability of the platform to maintain depth while operating near the surface.

This research is a part of a larger international program led by the DSTG aimed at better understanding the near surface manoeuvring performance of submarines to support the acquisition and sustainment of submarines. This includes access to experimental data from overseas partner facilities and benchmarking of numerical capability.