The reduction of underwater noise radiated from vessels and underwater vehicles prevents
product problems and increases added value. One of the sources of underwater radiated noise is
the propeller that produces the propulsion of a vessel or underwater vehicle. This article describes
the method for analyzing the unsteady vortices that are generated around blades with high
accuracy using CFD. Unsteady vortices cause singing noise among propeller noises. For the
analysis method, ELES, which is a combination of RANS with a low calculation load and LES with
a high calculation load, was used on understanding the ship-scale phenomenon with a relatively
low calculation load. We chose the case in which the blade model was fixed in a uniform flow as
the stage that precedes its application as a propeller. The general-purpose calculation domain
decomposition method for ELES was constructed. We will develop low noise propellers by applying
this method to propeller design.
