Differences between a laminar code and a les one

ben

hi,all I am fresh in LES programming,I have a unsteady laminar flow pragram using cartesian grid ,colocated variable arrangement,and pressure is solved using SIMPLE method,implicit Euler method for time marching . Now I want to develop a LES code based on this laminar code. (first smagrinsky then dynamic LES code)I have the following questions:

1.Is the following statement right? The main difference between laminar and lES is the latter adds a eddy viscosity,so I need only add a subroutine for calculating the eddy viscosity,and the unsteady terms ,convecting terms and the source terms can remain unchanged .The difference between smagrinsky and dynamic model lies in only the eddy viscosity solver.

2.Can i still use SIMPLE to calculate Pressure,if fractional step method is better?

3.What is the most simple case to test the LES code? Maybe cases without walls is better? Can someone help to tell me the definite domain size and resolution in domain and time? How many time steps is enough?

4. Using fine enough grid and time step ,Can the laminar code be used to do DNS calculation?

5.If cases with wall boudary is include what changes should be made to the laminar code to account for the LES wall boundary?

Any comment is greatly appreciated. Thanks