Trans RINA, Vol 156, Part B2, Intl J Small Craft Tech, Jul-Dec 2014


for all values of Ae /A0


10KQ KT


Figure 11: Model propellers with: P/D=1.66, =0.50


0 10KQ KT


Figure 12: Coefficients KT, KQ and  of the model with: Ae /A0=0.78, P/D=1.38 and =0.71 7. CONCLUSION


Model propeller series are used for the design of a ship propulsion system, propeller and engine. Computing the geometric quantities of the propeller and engine power is done using a computer program, i.e. an expert system. Prior to the development of this program, mathematical models of model


propeller series, which are its


component part, are required. This modeling can be done using standard mathematical functions or using spline functions and relational databases.


B-54


Modeling using spline functions is unambiguous, i.e. anyone who does it obtains the same result, because it does the interpolation between the original data and in


©2014: The Royal Institution of Naval Architects


Modeling using standard functions is ambiguous and approximating, i.e. each of the authors of models makes his own model which makes a smaller or a greater error in relation to original data. Existence of an error in mathematical modeling of some propeller series increases the degree of unreliability in calculation, since we are not sure when we made an error and how great it is.


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