Red-Emi - Reduction of hydroacoustic emission from propulsion systems

Red-Emi: "Reduktion der hydroakustischen Emission von Propulsionssystemen"

Since the beginning of motorized shipping the anthropogene hydroacoustic noise level has risen continuously. Research has shown, that marine wildlife is negatively affected by this noise. Maritime regualtion societies have recently begun to regulate noise emissions from ships. In order to meet the current and coming regulations and to protect the biodiversity in the sea, the joint research project Red-Emi aims to evolve simulation techniques for the calculation of underwater radiation from ships.

During the design of propulsion systems the accurate prognosis of noise sources during operation can only be considered if efficient tools to calculate these are available. The approach in Red-Emi is two-fold: improving simulations and creating an online artificial neural network.

The simulation of noise radiated from cavitating propellers with propeller caps or rudders intersecting the propeller vortex sheet and cavitation will be improved by modeling the interaction with an efficient boundary element method. In addition to improving the methods for sheet and tip-vortex cavitation, a model for hub-vortex cavitation will be developed and the contribution of the gear in rudder propellers is investigated. Detailed RANS/LES simulations will be performed to verify the models.

In order to improve the efficiency in the early stages of the design process, an online artificial neural network (ANN) will be designed and trained successively. The successive training will provide a method to provide mutiple partners the possibility to share one ANN and profit from this network trained with a large data set. At the same time, the confidential training data is not disclosed.

Subproject: KRawall - Calculation of underwater sound emitted by propulsion systems with rudders or boss cap fins

KRawall:  "Kalkulation des durch Propulsionssysteme mit Rudern oder Flossenkappen emittierten Unterwasser-Schalls"

This research project is focused on the flow simulation for propulsion configurations with a propeller and ship appendages like rudders or fins and the resulting acoustic emission. To enable the ship designer to make fast predictions of this type these interactions will be implemented in an efficient flow simulation method. In a first step, detailed simulations will be used to develop simplified models that are able to realistically model the interactions. After the simplified models are implemented, the new method will be applied to evaluate a rudder propeller as well as a propeller with boss cap fins regarding their acoustic emissions. Based on the results, a neural network capable to predict noise emissions of such propulsive configurations will be designed and trained. In each case, the propeller inflow will be modeled by a refined database-supported method.

The investigated topics are therefore:

  • Efficient prognosis of propeller sheet cavitation,
  • vortex cavitation on propeller tip and hub vortices and
  • deformation of free vortices and their interaction with other lifting surfaces.

In addition to these fields the research project also aims to predict the ship wake for cases where only the ship main particulars are known and to develope a neural net for noise prediction of whole ship propulsion arrangements that can be trained online.


Project Acronym RED-EMI
Project Title Reduktion der hydroakustischen Emission von Propulsionssystemen; Kalkulation des durch Propulsionssystemen mit Rudern oder Flossenkappen emittierten Unterwasser-Schalls
Duration 2022-01-01 - 2024-12-31
Principal Investigator Moustafa Abdel-Maksoud
Researchers Robert Beckmann, Raphael BĂ©vand


This project is funded by the Federal Ministry of Economic Affairs and Climate Action of Germany