Reducing the risk of blood clots in artificial heart valves
(PHYSorg.com Physics)

Most people are familiar with turbulence in aviation: certain wind conditions cause a bumpy passenger flight. But even within human blood vessels, blood flow can be turbulent. Turbulence can appear when blood flows along vessel bends or edges, causing an abrupt change in flow velocity. Turbulent blood flow generates extra forces which increase the odds of blood clots to form. These clots grow slowly until they may be carried along by the bloodstream and cause stroke by blocking an artery in the brain.