# How would you swim in inviscid water?

The viscosity of water creates drag on swimmer's body so its effect is to slow down the swimmer. However the viscosity seems to be essential for pushing the water backwards by the swimmer's arms and legs. Would a human be able to swim in water with much lower viscosity? What standard stroke (front crawl, breaststroke, butterfly) would work best/worst? How would a lower viscosity affect fish motion in water?

• Drag coefficient depends rather weakly on Reynolds number and hence on viscosity. So even if viscosity decreased several times (if the density remained unchanged) the drag coefficient change would be much smaller so the dynamic of swimming probably wouldn't change much. – user23660 Jun 11 '13 at 15:04
• Ref – Trimok Jun 11 '13 at 18:39

• Why should we assume that drag is dominated by viscosity while the stroke is dominated by inertia forces? The Reynolds number R is the ratio of the inertial to viscous forces, and R goes as $v l$, so a smaller object (arm) which is moving faster would have about same R as the whole body - correct? – Maxim Umansky Jun 11 '13 at 19:33