Influence of heeling angle on sailing yacht seakeeping characteristics

Jedrilice se smatraju teorijski jednim od najsloženijih plovnih objekata, upravo iz razloga što plove na granici dvaju fluida, vode i zraka. Predstavljaju točku ravnoteže hidrodinamičkih sila trupa i aerodinamičkih sila jedara. Uz pretpostavku da jedrilicu možemo promatrati kao kruto tijelo koje se giba, hidrodinamičke sile trenutno će i značajno utjecati na aerodinamičke komponente i obrnuto. Budući da često plovi u nagnutom položaju, iznimno je važno poznavati prirodu njenog ponašanja na valovima, kako u uspravnom tako i u nagnutom položaju. U ovome radu, problemu pomorstvenosti jedrilice u uspravnom i nagnutom stanju pristupilo se koristeći metodu rubnih elemenata (eng. boundary element method) koja se temelji na potencijalnom strujanju fluida i linearnoj teoriji valova. Promatran je odziv dviju formi iz sustavne serije Delft Systematic Yacht Hull Series, u uspravnom i nagnutom stanju, za dvije brzine napredovanja i pet valnih duljina. Svi rezultati uspoređeni su s dostupnim eksperimentalnim podacima. U dodatku, na primjeru jednog broda i jedne brzine, problemu se pristupilo koristeći i približnu metodu regresijskih polinoma razvijenu baš za navedenu seriju trupova.In theory sailing yachts are one of the most complex floating objects designed today. Their complexity lies in the fact that they sail in two fluids at the same time, water and air. They are equilibrium point between hydrodynamic forces produced by hull motion in the water and aerodynamic forces inducted by the sails sailing in the wind. Assuming the sailing yacht a moving rigid body, hydrodynamic forces will significantly influence aerodynamic forces and vice versa. Since sailing yachts are designed to sail in heeled position, it is obligatory to familiarize with predicting the nature of their motion in waves, both in upright and heeled condition. This thesis approaches the problem of sailing yacht seakeeping characteristics using the Boundary Element Method, based on potential flow and linear wave theories. Two Delft Systematic Yacht Hull Series hull forms have been observed, in upright and heeled condition, for two sailing speeds and five wave lengths. All the numerical results have been compared to available experimental towing tank results. In appendix, as an example, the problem has been approached using approximation regression polynomial method developed specifically for above mentioned hull series. One hull form and one speed have been investigated by this method