Bernoulli principle12/3/2023 A sail has lower air pressure on the front (leeward) side and more pressure on the rear (windward) side. An airplane wing has lower pressure on the top side of the wing and higher pressure on the bottom. Lift is the result of unequal air pressure on one side vs the other. So "lift" doesn't push the boat up, it pushes it forwards and sideways.Īs for Bernoulli, there's nothing wrong with Bernoulli's principle, it just doesn't do a very good job of explaining why sailboat sails and airplane wings develop lift. For a sailboat sail, the fluid is air and the "lift" is a horizontal force that propels the boat forward (and also makes it lean). "Lift" is the component of this force perpendicular to the fluid flow. ![]() When a solid object is immersed in a moving fluid, the fluid exerts a force on the object and the object exerts a force on the fluid that is equal in magnitude but opposite in direction. To answer your question, "lift" is a defined term in aerodynamics with a different meaning than usual usage. It's a red herring that confuses students without giving them any insight into how to sail. US Sailing does not use Bernoulli's principle in their instruction materials to explain how sailboats move and we do not use it in our instruction program (I am the manager of a learn to sail program with ten US Sailing Certified Instructors). Often both.įrom a layman's perspective, Bernoulli's principle does more to obscure the issue than it does to enlighten. vector calculus, partial differential equations, boundary conditions, the Navier-Stokes equation, etc.) are either so confusing that few readers can follow them, or they are just out and out wrong. Unfortunately, most attempts to explain lift using Bernoulli's principle without the overall mathematical context (i.e. ![]() Bernoulli's Principle is one very small piece of a large mathematical theory that explains lift.
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |