ABSTRACT
Whenever wind blows past a stationary obstacle, the obstacle is subjected to a force. A blowing wind is able to rustle the leaves on a tree, while a strong wind can even uproot a tree. Stationary structures such as chimney stacks, tall buildings, bridges, electrical transmission lines, and broadcast transmission towers are subjected to forces from blowing winds. An object moving in atmosphere has to move against a stationary mass of air, which prevents it from moving. The moving object has to overcome this resistance. Ideal-flow theory stipulates that the fluid is incompressible and nonviscous. A differential equation fundamental to the ideal-flow theory is Laplace’s equation. Flow patterns that are developed by ideal-flow theory are for irrotational flow. Flow of air or water in a region where the streamlines converge usually approximates irrotational flow closely. A real fluid is viscous and compressible.
