Fstentmtient

Fluid flow around objects: p + ½ρv² + ρgh = constant. Top: a streamlined body (a Rankine oval, made from a source and a sink in a uniform stream). The flow splits smoothly around it and joins up again behind it. Middle: a cylinder. The flow around it is potential flow, and a von Kármán vortex street sheds from it, alternating top and bottom. It uses the measured Strouhal number fD/U = 0.2 and Kármán's stable spacing h/l = 0.281. Bottom: a teardrop (a Joukowski aerofoil). The arrows are the surface pressure from Bernoulli, p − p∞ = ½ρ(U² − v²). They point in where the flow slows (the nose and the tail) and out where it speeds up (the shoulders). Every particle moves at the real speed of the flow. Faster flow means lower pressure.