Book contents
- Frontmatter
- Contents
- Preface
- Nomenclature
- Abbreviations
- Figure Acknowledgements
- 1 Introduction
- 2 Propulsive Power
- 3 Components of Hull Resistance
- 4 Model-Ship Extrapolation
- 5 Model-Ship Correlation
- 6 Restricted Water Depth and Breadth
- 7 Measurement of Resistance Components
- 8 Wake and Thrust Deduction
- 9 Numerical Estimation of Ship Resistance
- 10 Resistance Design Data
- 11 Propulsor Types
- 12 Propeller Characteristics
- 13 Powering Process
- 14 Hull Form Design
- 15 Numerical Methods for Propeller Analysis
- 16 Propulsor Design Data
- 17 Applications
- Appendix A1 Background Physics
- Appendix A2 Derivation of Eggers Formula for Wave Resistance
- Appendix A3 Tabulations of Resistance Design Data
- Appendix A4 Tabulations of Propulsor Design Data
- Index
- References
8 - Wake and Thrust Deduction
Published online by Cambridge University Press: 07 September 2011
- Frontmatter
- Contents
- Preface
- Nomenclature
- Abbreviations
- Figure Acknowledgements
- 1 Introduction
- 2 Propulsive Power
- 3 Components of Hull Resistance
- 4 Model-Ship Extrapolation
- 5 Model-Ship Correlation
- 6 Restricted Water Depth and Breadth
- 7 Measurement of Resistance Components
- 8 Wake and Thrust Deduction
- 9 Numerical Estimation of Ship Resistance
- 10 Resistance Design Data
- 11 Propulsor Types
- 12 Propeller Characteristics
- 13 Powering Process
- 14 Hull Form Design
- 15 Numerical Methods for Propeller Analysis
- 16 Propulsor Design Data
- 17 Applications
- Appendix A1 Background Physics
- Appendix A2 Derivation of Eggers Formula for Wave Resistance
- Appendix A3 Tabulations of Resistance Design Data
- Appendix A4 Tabulations of Propulsor Design Data
- Index
- References
Summary
Introduction
An interaction occurs between the hull and the propulsion device which affects the propulsive efficiency and influences the design of the propulsion device. The components of this interaction are wake, thrust deduction and relative rotative efficiency.
Direct detailed measurements of wake velocity at the position of the propeller plane can be carried out in the absence of the propeller. These provide a detailed knowledge of the wake field for detailed aspects of propeller design such as radial pitch variation to suit a particular wake, termed wake adaption, or prediction of the variation in load for propeller strength and/or vibration purposes.
Average wake values can be obtained indirectly by means of model open water and self-propulsion tests. In this case, an integrated average value over the propeller disc is obtained, known as the effective wake. It is normally this average effective wake, derived from self-propulsion tests or data from earlier tests, which is used for basic propeller design purposes.
- Type
- Chapter
- Information
- Ship Resistance and PropulsionPractical Estimation of Propulsive Power, pp. 144 - 165Publisher: Cambridge University PressPrint publication year: 2011