engleski

MARHYDRO - Seakeeping Educational Program

This paper discrabes an educational sekeeping software, based on ordinary strip theory of Gerritsma and Beukelman and modified strip theory of Voughts, derived and explained in seakeeping text books of A.R.J.M. Lloyd, R. Bhattacharrya and others. Local hydrodinamic coefficients can be calculated using 2-paramiter Lewis, or very accurate 9-parameter close-fit conformal mapping. Equations are solved for coupled simetrical and coupled non-simetrical motions in complex form, which results are transfer functions - RAOs and phase lags at the ship’ s center of gravity. The harmonic translations, velocities and accelerations can be calculated in the three directions in any point at the ship. Dynamic shear forces, bending and torsional moments can aslo be obtained. Viscous roll damping can be calculated using semi-emirical method of Ikeda, Himeno and Tanaka. ITTC and a mean JONSWAP wave spectrum are used to calculate ship’ s responces in irregular waves. This software has been made using MS Excel and MS Visual Basic, Windows well known programs. Higly interactive, this program is very suitable for educational purposes. MARHYDRO can also be used for ship’ s exploatation and ship design purposes. Code validation and verification has been provided for ITTC S-175 Container Ship.

seakeeping; strip theory; education

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