Verbesserte Prognose der durch die Wechselwirkung zwischen Schicht- und Spitzenwirbelkavitation bedingten Druckschwankungen höherer Ordnung - Numerische Simulation der Kavitationsvorgänge an der Propellerblattspitze


Project Acronym
HiOcav - HIOsim
 
Project Title
Improved Prediction of Higher-Order Pressure Fluctuations Caused by Interaction Between Sheet and Tip Vortex Cavitation
 
Funding Code
03SX435C
 
 
Principal Investigator
 
 
Status
Abgeschlossen
 
Duration
01-06-2017
-
31-05-2020
 
 
Contractor Organization(s)
 
Project Abstract
Cavitation on ship propellers creates pressure fluctuations that are noticeable in vibrations and audible noise. Since the complete prevention of cavitation limits the efficiency of the propeller in common applications, a better understanding of the mechanisms behind the dynamics of propeller-induced pressure fluctuations due to cavitation is necessary. The pressure fluctuations occur at different frequencies, which are considered in multiples of the blade frequency. The dominant frequencies vary depending on the cause: ranging from the first order as a result of the displacement effect and sheet cavitation to higher orders due to tip vortex cavitation. From experiments it is known that sheet and tip vortex cavitation frequently interact. This project aims to provide valuable insights into the dynamics of propeller-induced pressure fluctuations.
The project will carry out experimental investigations and further develop corresponding measurement technologies, such as the three-dimensional reconstruction of cavity volumes. Together with the numerical investigations of flow details, the phenomenological understanding of the interaction between sheet and tip vortex cavitation will be greatly expanded upon. The findings will be incorporated into the development of efficient, numerical prediction methods. The HiOcav joint project gains valuable new insights on cavitation within an interdisciplinary cooperation between university and industrial project partners – insights which will also be applied in the development and design of propellers.

HiOsim
Within the HiOsim subproject, FDS numerically investigates flow details and further develops numerical prediction methods. For example, flow details that are not measurable in experiments will be obtained from RANS simulations. Further, with a new numerical model for the dynamics of tip vortex cavitation and its coupling with an improved sheet cavitation model by the panel code panMARE, an advanced tool for prediction of the occurring cavitation will be developed. By further developing the sheet cavitation model and integrating the new model for tip vortex cavitation and their coupling into panMARE, our ability to predict higher-order pressure fluctuations will be greatly improved.