[sir--kris]

Hi guys,

I facing to a problem in Fluent Ansys 16:
I wish to symulate the progress of the reflecting pressure waves
into an exhaust system of a 2 strokes engine.
As first step I wanna symulate a very simple axisymmetric 2D duct
made up of a first part with constant section and a second part of a divergent section. The gas can be simple air (in this first step).
Pressure in atm.

The goal would be to can see how the reflecting pressure (low pressure
in this case) waves coming back after the exhaust port opening and
gas emission.

I think I need of a UDF (that I can't write ) simulating the pressure evolution (or maybe the flow velocity, I don't know) on the inlet. I think maybe a spike type function and make a temporal (transient) simulation until the pressure wave come back to the inlet.

I don't know how set up the problem about the inlet BC.
Perhaps I have to set only a pressure simulating a pressure wave at
sonic velocity? Or only a sonic flow (flow velocity)?
Or maybe both?
What kind of solver setting or other thinghs do you suggest?

Please feel you free to ask anything else you need to understand the problem.

I attach here the initial file .cas concerning the problem.

A gif that explanes the phenomena:

https://it.wikipedia.org/wiki/Camera...e_Zweitakt.gif

Kind regards

[sir--kris]

Sorry guys I has forgotten to attach the cas file.

Regaaaaards

[sir--kris]

Hi, no one tip?