Resistance Tests on a 2-Foot Model Submitted by Prof. K. davidson

摘要

The results show that ship models two feet or less in length have their useful range of speeds in a very critical region. To obtain consistent results particular attention must be given to the temperature of the water, surface tension as affected by the cleanness of the water's surface, the degree of smoothness of the model's surface, and the nature of the entering or leading edge of the model. These factors are of such nature that their combined effects make ship models, of length two feet or less, impracticable for general test purposes. However, any careful study of this critical region is illuminating in regard to the transition from laminar to mixed flow and then to fully developed turbulent flow. For this reason and for the fact that scale effect is intimately tied up with the nature of the flow, work with these small models possesses real value. (Author)