Analysis of infinite length hydrofoil near free surface

In the conceptual design of a submarine quick estimation of hydrodynamic coefficients of a body and appendages is needed. In these methods, formulas are given for different coefficients and for the control surfaces, using two-dimensional factor provided for hydrofoil in wing sections theory books, are suggested. A Critical point in using these coefficients of wing sections theory books is, these coefficients are calculated for far from the free surface and for near the free surface is needed to be improved. Then in In the present work, Based on the assumption of potential flow and boundary element method a computer program has been developed to calculate the coefficient of hydrofoils with various sections in near the free surface. results in submerged is in full compliance with experimental and numerical results and in the near the free surface, these results are consistent with good accuracy.