Explicit filtering in LES

TJ

Hi,

I have been doing some LES simulations using the Finite-Volume formulation as an implicit top-hat filter. I would now like to implement explicit filtering into my code. However I have so far only succeded in confusing myself.... If anyone can answer the following questions I would be most gratefull.

In the momentum equation the velocities become filtered velocities and the pressures become filtered pressures. Do I need to determine these from the actual velocities using the filter?? can I do the opposite and determine the actual velocity (and therefore the fluctuation) by reversing the filter and applying it to the filtered variables????

Additionally I am unsure about whether to represent the subgrid dissipation as a source/sink term in the equation or as an additional viscosity - what do you recommend??

Thanks