Changing the porosity of cells per time step

NeilmBarker · March 22, 2019, 08:59

UDF Newbie here so please be gentle.

I'm trying to simulate a valve closing without the valve being there. This is to hopefully make it a bit easier to compute. I've modelled a ram pump and would like to look at the water hammer effect further up the pipe network.

I was thinking, the easiest way was to create a set of porous cells at the end of the pipe and change them from letting fluid through to not letting it through. I was hoping the porosity of a range of cells could be altered per time step. I can then complete multiple models with different valve closing times.

My question is, do you think this is achievable via the UDF? Or am I going down the wrong route? I’ve been wanting to start UDF coding for some time now. But this problem may not be the one to start with.

From what i've learnt so far doing CFD is, “there's more than one way to skin a cat”. “And some cats are easier to skin than others..”

Thanks,

Neil

AlexanderZ · March 25, 2019, 01:30

What cats are you talking about?

Did you try to change porosity manually to stop flow? Does it work?

best regards

March 22, 2019, 08:59	Changing the porosity of cells per time step	#1
NeilmBarker New Member Neil Barker Join Date: Nov 2018 Posts: 1 Rep Power: 0	UDF Newbie here so please be gentle. I'm trying to simulate a valve closing without the valve being there. This is to hopefully make it a bit easier to compute. I've modelled a ram pump and would like to look at the water hammer effect further up the pipe network. I was thinking, the easiest way was to create a set of porous cells at the end of the pipe and change them from letting fluid through to not letting it through. I was hoping the porosity of a range of cells could be altered per time step. I can then complete multiple models with different valve closing times. My question is, do you think this is achievable via the UDF? Or am I going down the wrong route? I’ve been wanting to start UDF coding for some time now. But this problem may not be the one to start with. From what i've learnt so far doing CFD is, “there's more than one way to skin a cat”. “And some cats are easier to skin than others..” Thanks, Neil

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March 25, 2019, 01:30		#2
AlexanderZ Senior Member Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 34	What cats are you talking about? Did you try to change porosity manually to stop flow? Does it work? best regards