Experimental Study On Force Distribution During Slamming Event With Hydrophobic Surface
Predictingimpact forces and pressure distribution during water entry is of great importance in designing marine structures, missiles and seaplanes that experience slamming loads. In water entry of blunt bodies, different fluid dynamics phenomena like jet formation, cavity formation, water splashing, flow separation on solid surfaces and air entrapment between solid and liquid surface have been studied for decades. Our study is aimed at understanding and modeling the dynamics of slamming under an extended range of parameters including hydrophobic surfaces. In this study, slamming phenomenon has been demonstrated by using a cylindricalspecimen. The effect of hydrophobic surfaces is studied through flow separation and evolution of water splashing at various velocities during the impact process.Digital images at impact process were captured using a high speed camera. At the same time, we measured the force distribution on the surface of the test body during impact by employing strain gages. Here we present the results of our experimental work on water entry test of hydrophobic coated bodies. First we present results from our water entry test, using a cylinder. Second, we consider how flow separation on solid surfaces and splash formation are modified on these bodies that have hydrophobic coating. Finally, we present the comparison in slamming coefficient and pile-up coefficient for the test cases.
Index Terms-"water entry, hydrophobic and strain".