ESTIMATION OF HYDRODYNAMIC IMPACT LOADS AND PRESSUREnDISTRIBUTIONS ON BODIES APPROXIMATING ELLIPTICALnCYLINDERS WITH SPECIAL REFERENCE TOnWATER LANDINGS OF HELICOPTERS

摘要

An approximate method for computing water loads and pressure dis¬tributions on lightly loaded elliptical cylinders during oblique water impacts is presented. The method is of special interest for the case of emergency water landings of helicopters. This method makes use of theory developed and checked for landing impacts of seaplanes having bottom cross sections of V and scalloped contours.nAn illustrative example is given to show typical results obtained from the use of the proposed method of computation. The accuracy of the approximate method was evaluated through comparison with limited experi-mental data for two-dimensional drops of a rigid circular cylinder at a trim of 0° and a flight-path angle of 90°. The applicability of the proposed formulas to the design of rigid hulls is indicated by the rough agreement obtained between the computed and experimental results. A detailed computational procedure is included as an appendix.