[subramanyamn]

Hello,

I'm trying to understand the behaviour of a pressure wave-front as it enters a diverging / converging section in a tube. I tried looking it up in John D. Anderson's 'Modern Compressible Flow with a Historical Approach' text, but it only discusses unsteady waves in uniform closed pipe.

OpenFoam's rhoCentralFoam has a Sod's shock-tube tutorial which deals with uniform cross-section again. I, after reading about behaviour of instruments, know when a pressure wave enters an area of greater cross-section, an expansion wave gets sent in the opposite direction. I am unable to visualize this in a converging-diverging geometry I developed using rhoCentralFoam. I'm unable to understand where I am wrong or how this solver actually considers the area term.

I require help regarding understanding the significance of area in a shock tube. Can someone please help?