Momentum Souce term

Chary_w0w · May 30, 2020, 13:55

Hey everyone,

I want to introduce an acceleration in my domain. I'm aware i must do it using the "momentum source term".

My question is regarding the units. Star-CCM uses N/m^3 and, of course, my acceleration is in m/s^2. Do I need to convert the units? I thought I'd read somewhere that we can put it as an acceleration and star would return it, in the units star uses.

Anyway, thank you in advance and hope you're all safe.

fluid23 · June 2, 2020, 11:19

I am not sure about that, I have not seen that ability but it could be true.

I believe that if you divide the source term by density, you are left with acceleration, no?

F/V (N/m^3) / rho (kg/m^3) = a (m/s^2)

So source term is acceleration x density.

May 30, 2020, 13:55	Momentum Souce term	#1
Chary_w0w New Member Francisco Machado Join Date: Apr 2020 Location: Portugal Posts: 4 Rep Power: 6	Hey everyone, I want to introduce an acceleration in my domain. I'm aware i must do it using the "momentum source term". My question is regarding the units. Star-CCM uses N/m^3 and, of course, my acceleration is in m/s^2. Do I need to convert the units? I thought I'd read somewhere that we can put it as an acceleration and star would return it, in the units star uses. Anyway, thank you in advance and hope you're all safe.

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June 2, 2020, 11:19		#2
fluid23 Senior Member Matt Join Date: Aug 2014 Posts: 947 Rep Power: 17	I am not sure about that, I have not seen that ability but it could be true. I believe that if you divide the source term by density, you are left with acceleration, no? F/V (N/m^3) / rho (kg/m^3) = a (m/s^2) So source term is acceleration x density.