The wake fields between model and full-scale show differences because of the underlying physics. In model-scale the boundary layer is thicker relative to full-scale and the bilge vortex more pronounced. This results in differences in the inflow to the propeller between model and ship, which should be considered when designing the propeller. Through the use of numerical methods, the wake field can be calculated for both the model and the ship. Thus it is possible, already while designing the ship lines, to evaluate the wake field and the influence of geometry modifications or appendages. Further, the wake field can be made available for propeller design.
The numerical simulations offer the following advantages:
- Calculation of the wake field in the preliminary design stage
- Calculation of the wake field for the Reynolds number of the vessel
- Evaluation of the velocity components of the wake for any radius and angular increments
- Visualising the inflow and presentation of the causes (for example, separations) for potential irregularities
Context Related References / Research Projects
[1] Abdel-Maksoud, M., Lübke, L.: Berechnung des Nachstromfeldes der Großausführung, 97. Hauptversammlung der Schiffbautechnischen Gesellschaft, Hamburg, 20.-22.11.2002
[2] Lübke, L.: Calculation of the Wake Field in Model and Full-scale, NAV 2003, International Conference on Ship and Shipping Research, Palermo Italy, 24.-27. June 2003
[3] Lübke, L.: Calculation of the Wake Field in Model and Full-scale, CFX Conference 2003, Garmisch-Partenkirchen, 04. – 06. November 2003
[4] Lübke, L.: Validation of CFD Results behind the Working Propeller of a Ship Model, 7th Numerical Towing Tank Symposium, Hamburg, 03.-05. October 2004
[5] Lübke, L., Mach, K.-P.: LDV Measurements in the Wake of the Propelled KCS Model and its Use to Validate CFD Calculations, 25th Symposium on Naval Hydrodynamics, St. John’s, Newfoundland and Labrador, Canada, 08-13 August 2004
[6] Lübke, L.: Berechnung des effektiven Nachstromfeldes der Großausführung, 11. SVA-Forum, Potsdam, 09.11.2004
[7] Lübke, L.: Formoptimierung unter Berücksichtigung der Charakteristik des Nachstromfeldes, 4. SVA Forschungsforum „Theoria cum praxi“, Potsdam, 27.01.2011