Calculation of Hydrodynamic Resistance Coefficient of Diver with and without Diving Equipment by CFD Method at Surface and Near Surface Condition

The main purpose of the present study is to examine the effects of diving equipment include oxygen tank, tank valve, hose, mouthpiece and diving fins on increasing the resistance and resistance coefficient of the diver's body at free surface condition. The other purpose is calculation of the resistance and resistance coefficient of a diver with equipment in different positions. This study uses a computational fluid dynamics methodology. SST K-ω turbulent model is implemented in the Star-CCM+ application and is applied to the flow around a three-dimensional bare hull of an adult human during diving with effect of carrying diving equipment. Four different positions are considered: diving horizontally, diving with attack angle of 30 degrees, diving with attack angle of 45 degrees and diving with attack angle of 45 degrees while knees are bent at 45 degrees backward. The results for horizontally diving are compared with the bare hull of adult human without equipment. All the simulations are done in surface and near surface situations with two-phases simulation. The flow velocities between 0.5 and 2m/s with increasing step of 0.5m/s are considered in the simulations which are typical speed of swimmers. The results show that using diving equipment leads to increasing total resistance about 90% to 128% during near surface swimming and about 28% to 62% in surface swimming just in higher velocities. The results of this research can be used for designing all types of marine propulsion vehicles, water scooter, and all swimming thrusters.