negative velocity inlet

hebeldebel · July 22, 2015, 11:51

Hi,

I wrote a field function to control the inlet velocity of a boundary:

cos(${Time}*2*3.14*2)*10

It works until the velocity reaches 0 and then rises again, I never get a negative velocity at the inlet. I ran reports, which showed that the output of the field function was indeed negative, but Star CCM+ turned it into a positive value for the velocity inlet.

It seems like a velocity inlet cannot be used as an outlet by simply putting a minus in front of the value. What would you do to accomplish this?

kind regards,

hebeldebel

fluid23 · July 22, 2015, 17:33

maybe try using a mass flow inlet? I know those can go negative.

honestly, this seems like a bug. you may want to submit it to CD-Adapco so they can resolve it.

July 22, 2015, 11:51	negative velocity inlet	#1
hebeldebel Member Join Date: Jan 2014 Posts: 40 Rep Power: 12	Hi, I wrote a field function to control the inlet velocity of a boundary: cos(${Time}23.142)10 It works until the velocity reaches 0 and then rises again, I never get a negative velocity at the inlet. I ran reports, which showed that the output of the field function was indeed negative, but Star CCM+ turned it into a positive value for the velocity inlet. It seems like a velocity inlet cannot be used as an outlet by simply putting a minus in front of the value. What would you do to accomplish this? kind regards, hebeldebel

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July 22, 2015, 17:33		#2
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 18	maybe try using a mass flow inlet? I know those can go negative. honestly, this seems like a bug. you may want to submit it to CD-Adapco so they can resolve it.