question to the fluid mechanicans
 

Hi,
I've problems with the model validation for my fluent simulation. I need an analytical equation for ime dependant pressure reduction...


- The simplified model:

At the beginning a compressible fluid (visco-elastic Polymer) is under high pressure und Temperature in a fixed geometry (think of a block)

Now one of the Faces is removed and the fluid is able to expand into the free room (space behind the removed face).

At the end of the free space is a pressure outlet, so that the material can reduce the pressure to standard atmosphere (1 atm)


My question is: How is the physical description of a time dependant pressure decrease for a fluid material that is compressible or better
(visco-elastic)

- In my opinion viscosity (a kind of inertia) have to influence the compression and decompression process. May I use a modified Bernoulli equation or a special differential equaution for the time dependant pressure drop?