- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- A study of the hydrodynamic performance of Voith-Schneider...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
A study of the hydrodynamic performance of Voith-Schneider propelled escort tugs Ratcliff, Arlon J.T.
Abstract
The hydrodynamic performance of a typical modern escort tug, as it relates to indirectly applied ship handling force, is examined through an experimental and theoretical study. Experimental results are presented from a series of tow tank tests performed on a 1:18 scale model of the Voith-Schneider Propelled (VSP) escort tug, AJAX. Steady state flow patterns close to the hull are investigated and possible areas of focus for improvement are highlighted. Using this information, three alternative skeg configurations are proposed and tested. A semi-empirical numerical model, based on current and previous experimental data, is developed as a standard basis of comparison for the alternative configurations. The numerical model also allows prediction of performance for hypothetical tug designs. A sensitivity analysis is performed using the numerical model to determine areas of focus for design optimization. No significant difference in performance was found between the alternative and baseline skeg configurations, indicating more comprehensive design changes are required to effectively improve escort performance. However, an alternative configuration, consisting of a skeg similar to the baseline skeg with a gap at mid- chord, achieved this comparable performance with 14% less lateral area, which may be of benefit to other aspects of tug performance. The results of the flow visualization study and sensitivity analysis indicate location of the skeg has a greater influence on performance than shape. Stability and tow point location are also relatively important. However, no single design parameter was identified for focus. Instead, design optimization requires a balance of several parameters. The numerical model can be used for this purpose. The numerical model produces performance estimates with an uncertainty of 15% of the maximum steering force. This uncertainty is adequate for initial estimates at the early stages of escort tug development.
Item Metadata
Title |
A study of the hydrodynamic performance of Voith-Schneider propelled escort tugs
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
2003
|
Description |
The hydrodynamic performance of a typical modern escort tug, as it relates to indirectly
applied ship handling force, is examined through an experimental and theoretical study.
Experimental results are presented from a series of tow tank tests performed on a 1:18 scale
model of the Voith-Schneider Propelled (VSP) escort tug, AJAX. Steady state flow patterns
close to the hull are investigated and possible areas of focus for improvement are
highlighted. Using this information, three alternative skeg configurations are proposed and
tested. A semi-empirical numerical model, based on current and previous experimental
data, is developed as a standard basis of comparison for the alternative configurations. The
numerical model also allows prediction of performance for hypothetical tug designs. A sensitivity
analysis is performed using the numerical model to determine areas of focus for
design optimization.
No significant difference in performance was found between the alternative and baseline
skeg configurations, indicating more comprehensive design changes are required to effectively
improve escort performance. However, an alternative configuration, consisting of a
skeg similar to the baseline skeg with a gap at mid- chord, achieved this comparable performance
with 14% less lateral area, which may be of benefit to other aspects of tug
performance.
The results of the flow visualization study and sensitivity analysis indicate location of the
skeg has a greater influence on performance than shape. Stability and tow point location are
also relatively important. However, no single design parameter was identified for focus.
Instead, design optimization requires a balance of several parameters. The numerical model
can be used for this purpose.
The numerical model produces performance estimates with an uncertainty of 15% of the
maximum steering force. This uncertainty is adequate for initial estimates at the early
stages of escort tug development.
|
Extent |
8274104 bytes
|
Genre | |
Type | |
File Format |
application/pdf
|
Language |
eng
|
Date Available |
2009-11-20
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
|
DOI |
10.14288/1.0080994
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Graduation Date |
2004-05
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.