# navier-stokes equations

 Few things in nature are as dramatic, and potentially dangerous, as ocean waves. The impact they have on our daily lives extends from shipping to the role they play in driving the global climate. From a theoretical viewpoint water waves pose rich challenges: solutions to the equations that describe fluid motion are elusive, and whether they even exist in the most general case is one of the hardest unanswered questions in mathematics. Africa isn't a continent that's famous for cutting edge research. But at the University of Stellenbosch, 50km East of Cape Town, South Africa, Kiran Dellimore and his team are engineering medical equipment that will save the lives of people all over the world. Latest projects include replacement heart valves made from kangaroo tissue and equipment to help resuscitate people in emergencies. In 1997 Andy Green was the first to break the sound barrier in his car Thrust SSC, which reached speeds of over 760mph. Now he and his team want to push things even further with a car called Bloodhound, designed to reach the dizzy heights of 1,000mph, about 1.3 times the speed of sound. Ben Evans explains how maths is used to build this car. Andy Green, Royal Air force pilot and Oxford maths graduate, is gearing up to break his own land speed record in Bloodhound SSC, a supersonic car designed to reach speeds of up to 1000mph. He tells Plus about the challenges — and the maths — behind this engineering adventure. Describing the motion of fluids is a huge and unsolved mathematical problem. There are equations that seem to describe it well, but their complete solution is way beyond reach. But could there be a simpler method? The physicist Jerry Gollub tells Plus about a new discovery which combines experiment with sophisticated maths. Peter Markowich is a mathematician who likes to take pictures. At first his two interests seemed completely separate to him, but then he realised that behind every picture there is a mathematical story to tell. Plus went to see him to find out more, and ended up with a pictorial introduction to partial differential equations. Phil Trinh discovers how maths helps solve the mysteries of flight and love. Learn about the aerodynamics of footballs and perfect your free kick. Goal keepers defend against the maths of the new World Cup ball Umbrella or no umbrella? New advances in weather forecasting will help us dodge hurricanes and protect against floods.