Bernoulli’s equation clearly models an idealized form of [[Fluid|fluid]] flow, since it does not account for [[Heat|heat]] loss through [[Friction|friction]]. This [[Ener|energy]] loss through friction is termed **head** **loss**, $h_l$​. $p_1+\rho gz_1+\dfrac{1}{2}\rho v_1^2=p_2+\rho gz_2+\dfrac{1}{2}\rho v_2^2+h_l$ Due to the complexity of friction, head loss is typically measured empirically and put in tables. Head loss can be broken into two components: - Major Losses: Friction loss due to flow through a long, straight pipe. - Minor Losses: Friction loss due to abrupt changes in geometry, like bends, nozzles, or valves. Major and minor losses typically have empirical or semi-analytical solutions which can be found in any standard fluid mechanics textbook.