Local Non-Linear Free Surface Effects for Hull Generating Elementary Waves

Abstract

The local non-linear free surface effects acting upon hull generating elementary waves are surveyed. Through the simplification of the exact free surface condition, the basis of the non-linear theory, the low speed theory and the linear theory is characterized.A non-linear wave theory developed as an extension of the geometrical optics is presented. The propagation of elementary waves generated on the hull from bow through stern is numerically traced. The non-linear effects integrated along the passage of waves in the non-uniform double body flow are discussed.Based upon the asymptotical expression for free waves far rear the ship where the remained non-linear effects are taken into account, wave resistance is evaluated for an Inuid model. Less prominent humps and hollows of the calculated wave resistance coincide fairly well with the towing test results within the moderate Froude numbers.