Which of the following rules are used in choosing the repeating variables in dimensional analysis :

1. Repeating variables should include the dependent variables
2. Repeating variables should contain all primary units used in describing the variables in the problem
3. Repeating variables should combine among themselves.
4. Repeating variables should not contain the dependent variables.



1 is false
In 2 repeating variables must be chosen in such a way that they should contain geometric property,flow property and fluid property
In 3 Repeating variables together must have same number of fundamental dimensions. Also No Two repeating group should have same dimentions
4 is true  dependent variable should not be selected as repeating variable

/* note :refer R.K.Bansal book on fluid mechanics */