3)Dimensional analysis A problem An incompressible. Newtonian fluid steady flow, through a long, smooth-walled, horizontal circular pipe \P,=f(D, p, u, r) The nature of function is unknown and the experiments are necessary We can recollect these variables into dimensionless products DAp OVD oV2 Variables from 5 to 2 #5 Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 5 p f (D V ) l  = , ,, 3) Dimensional analysis A problem. An incompressible, Newtonian fluid, steady flow, through a long, smooth-walled, horizontal, circular pipe. The nature of function is unknown and the experiments are necessary. We can recollect these variables into dimensionless products, Variables from 5 to 2.         =      VD V D pl 2