why we cant form the pi group by using repeating variable of (μ, ρ , v) or (D, v , μ ) ?
The Attempt at a Solution
according to the principle , when we choose the repeating variable , it cant form the dimensionless group , right ? for (μ, ρ , v) , i have (M/LT)(M/(L^3))(L/T) , i got (M^2)(L^-3)(T^-2)
for (D, v , μ ) , i have (L)(L/T)(M/LT) , i got ML(T^-2) , both group are not dimensionless, why is it a must to form group by using (D, ρ , v) ??