design algorithm of a free surface water tunnel to test the surface-piercing propellers (spp); case study water tunnel of babol noshirvani university of technology

surface-piercing propellers (spps) have been widely used in high speed craft due to some desirable features such as high efficiency, omission of resistance of equipment attached to the propeller and proper functioning of cavitation. unlike the submerged propellers, theoretical methods have no significant application on simulation of sppsbecause of problems related to modeling of these propellers. design of spps is mainly done based on empirical studies and model experiments. water tunnel or free surface cavitation tunnel is among the most important devices to perform spps model testing. in this paper, the design algorithm of a free surface water tunnel to test the spps has been described. the design and construction stages of the free surface cavitation tunnel of babol noshirvani university of technology are provided. also,calculation of its various sectors such as elbows, nozzle, settling chamber, test section, diffuser and calculation of pressure drops, proper pump selection and dynamometer  has been showed.