1. The problem statement, all variables and given/known data in this problem , the author make π1 = D(dp/ dx) / ρ( V^2) , and make π3 as μ/ ρVD , how if i want to make μ/ ρVD (reciprocal of reynold number ) as π1 and make D(dp/ dx) / ρ( V^2) as π3 ? 2. Relevant equations 3. The attempt at a solution since we know that π1 is function of ( π2 , π3 ) is it necessary to change μ/ ρVD (reciprocal of reynold number ) to reynold number (ρVD / μ ) ? which is correct ? Re = f ( D(dp/ dx) / ρ( V^2) , Ks/ D ) or μ/ ρVD = f ( D(dp/ dx) / ρ( V^2) , Ks/ D ) ? which is correct ?