Dear Experts, I am 4th year undergraduate who did experiments for drag reduction in swim cap. I had applied hydrophobic and hydrophilic coatings on my cap. My final results are shown in attachment below. The no cap has more drag than body with swim cap without coatings. There is not much different in drag coefficient for body with swim cap, hydrophobic coating and hydrophilic coating. The body with goggle has most drag which is noticeable in experiment as the body has most obstruction which creates turbulence. However, anyone knows what is happening for swim cap profile? why there is a sudden rise in acc for split second. Is it the turbulent Boundary layer has been tripped and therefore delay the flow seperation and reduces the wake?? I found it hard to explain. It appears that a streamline swim cap reduces the drag of a no cap polystyrene sphere.