EurekAlert! offers eligible public information officers paid access to a reliable news release distribution service. IMAGE: Time evolution (from left to right) of systolic turbulent blood flow past a bileaflet mechanical heart valve. view more  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. Patients with artificial heart valves are at a higher risk of clot formation. The elevated risk is known from the observation of patients after the implantation of an artificial valve. The clotting risk factor is particularly severe for the recipients of mechanical heart valves, where the patients must receive blood thinners every day to combat the risk of stroke. So far, it is unclear why mechanical heart valves promote clot formation far m...