Question

where AP, is the frictional pressure drop per unit length, w is the fluid velocity, d is the pipe diameter, p is the fluid density, u is the fluid viscosity and c is the pipe roughness (with units of length). Air flows through a smooth pipe (i.e. no roughness) of 0.3 m in diameter at a mean velocity of 25 m/s. A 1/10 model of the pipe is built made from the same material that can be operated with either air or water. Which fluid and at what velocity should be used in the model to achieve dynamic similarity between the model and the prototype?

It is smooth not rough for the question being asked

Answer 1

Air e Que) As foe prototype = 25 mls o Idoso 3m 0. for dynamic similacily, there should be a geometric similarity between model and prototype. let dm, Lom are the diametee and length of model and similarily dp, Lp for prototype. Now scale satio is 1/10 dm - Loma Lrabe dp 4 -O 10. - for dynamic similarily of prototy model Air O dom o dno Vm=? (Sud Reynolds Numbee all inilae ( model - Puede prototype Undm up do um 7 Cap Jup => /um = 250m/s)