Lifting Line Calculations for Hydrofoil Performance at Arbitrary Froude Number and Submergence. Part 1. Fixed Shape Elliptical Circulation Distribution,

摘要

Hydrofoil drag and lift prediction formulas using the lifting line approximation are evaluated numerically using a computer program developed for the purpose. Some results for selected aspect ratios and foil submergences are displayed in several plots of general interest and usefulness, for the case of an elliptic planform hydrofoil supporting an elliptic circulation distribution of fixed shape, but variable strength. Some preliminary comparisons between results obtained numerically and asymptotic formulas are discussed. These show that for certain extreme cases, the wave drag and the Froude-independent part of the lift correction are well predicted by asymptotic relations. For intermediate values of both Froude number and submergence ratio, the asymptotic relations give poor results for wave drag. At most all submergences and Froude numbers the existing asymptotic expressions for the Froude-dependent part of lift correction give poor results.