Sec. 50.9 



CALCULATION OF WAVEMAKING RESISTANCE 



217 



Total Resistonces for Norweqion Model 41, Representinq c Destroyer Form. 

 Corresponding FVoporti'ons o nd Form, Coeflicients- 



-^=10.21 



3.418 



F^°'f 



Cp= 0.653 Cx-0.80? 



Cg- 0.526 



©I 



For Lines of This Form, see Fig. 3.Q, 

 Sec. 3. 13, Volume I 



Includinq Friction Re&istanoe, 



Qs Derived from Anolvitic Treatment of 



i 1 ( — I J 1 1 ,— 



^Totol Estimated Resistance for Ship, 



Form Generated by Source Distribution C 

 [Lunde, J. K., IImV 1949. pp. 'l66-l90]. 



Includinq Friction Resistance, 

 QS Derived from Standard Model Test 



0.24 az(, 0.28 0.30 032 034 Q36 038 0.40 042 0.44 046 048 Q50 052 054 0.56 058 060 062 0.64 0.66 



Froude Number f„- V/t/oL 



Fig. 50.D Comparison of Total Resistances for Lunde's Destroyer Model, as Calculated and as Deter- 

 mined FROM Model Tests 



depicted in Fig. 3.Q of Sec. 3.13 of Volume I 

 [INA, 1949, Fig. 3, p. 188]. Except for the hump 

 in the curve of calculated resistance at a Froude 

 number F„ of about 0.30, much more pronounced 

 in the calculated data than in the experimental 

 data from a routine towing-model test, the agree- 

 ment is considered to be remarkably good. The 

 shift in the hump of the ©-curve at an F„ of 

 about 0.48, from its position on the theoretical 

 graph to that on the experimental curve, is con- 

 sidered due to the fact that the displacement 

 thickness of the boundary layer around the towed 

 model gives it a greater effective length than its 

 actual physical length. At least, its effective 

 length appears to be greater than that of its 

 counterpart in the real liquid. 



Other comparisons are given by the following, 

 some of them original and some taken from the 

 technical literature: 



(1) Weinblum, G. P., TMB Rep. 710, Sep 1950, Fig. 6 



on p. 22 and Fig. 7 on p. 24 



(2) Shearer, J. R., "A Preliminary Investigation of the 



Discrepancies Between the Calculated and Measured 

 Wavemaking of Hull Forms," NECI, 1950-1951, 

 Vol. 67, pp. 43-68 and D2I-D34 



(3) Havelock, T. H., "Wave Resistance Theory and Its 



Application," SNAME, 1951, Fig. 6 on p. 18; 

 Fig. 7 on p. 19 



(4) Birkhoil, G., Korvin-Kroukovsky, B. V., and Kotik, 



J., SNAME, 1954, Fig. 5 on p. 366. This is the first 

 diagram mentioned in item (3) preceding. 



50.9 Other Features Derived from Analytic 

 Ship-Wave Relations. Of great interest to the 



naval architect are the features, other than the 

 wavemaking resistance of a ship in deep water, 

 which the workers in this field have been able to 

 derive by the use of analytic methods and mathe- 

 matics. Among these may be mentioned (with 

 the source references): 



(1) Wavemaking resistance in deep water in 

 accelerated rather than steady motion. This is of 

 fundamental importance in the design and 

 operation of model testing basins and in the 

 conduct of ship trials over measured-mile courses. 



Wigley, W. C. S., "Ship Wave Resistance," Proc. 



Third Int. Congr. Appl. Mech., Stockholm, 1930, 



Vol. I, pp. 58-73, esp. Figs. 6-9 on pp. 68-70 

 Havelock, T. H., Quart. Jour. Mech. and Appl. Math., 



(Oxford), 1949, Vol. 2, p. 325ff and p. 419ff 

 Havelock, T. H., Proc. Roy. Soc, 1950, Series A, 



Vol. 201, p. 297ff. 

 Lunde, J. K., SNAME, 1951, pp. 40-44 



(2) Wavemaking resistance in steady motion in 

 an infinitely deep canal with veBtical walls. 



Sretensky, L. N., Phil. Mag., 1936, Vol. 22, p. 1005ff 

 Lunde, J. K., SNAME, 1951, pp. 44-50. 



(3) Wavemaking resistance in steady motion in 

 restricted waters. 



Havelock, T. H., Proc. Roy. Soc, 1921, Series A, 



Vol. 100, p. 499ff 

 Havelock, T. H., Proc. Roy. Soc, 1928, Series A, 



Vol. 118, p. 30ff 

 Weinblum, G. P., Schiffbau, 1934, Vol. 35, p. 83ff 

 Sretensky, L. N., Phil. Mag., 1936, Vol. 22, p. 1005fE 

 Weinblum, G. P., STG, 1938, Vol. 39, p. 166ff. 



