why cant we use bernoulli's equation for high velocity flights ? what changes when air is compressed ? does density change ?
There is a form of Bernoulli's equation that handles compression and expansion. The density changes, lower during expansion, greater during compression. Since pressure is energy per unit volume, as opposed to energy per unit mass, it's affected by density. The terms in Bernoulli's equation include a pressure term, and two other terms multiplied by density (instead of mass).What changes when air is compressed? does density change ?
Bernoulli is a simplied model that doesn't deal with factors like turbulent flow. It doesn't account for the internal energy of the eddies in a turbulent flow. It doesn't account for temperature changes due to compression or expansion of air. It doesn't deal with supersonic flows that involved shock waves. The more generalized Navier Stokes equations handle most of this, but generally they can't be solved, so an airfoil model uses some simplication of Navier Stokes.Why cant we use bernoulli's equation for high velocity flights?