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Mass conservation
Posted May 9, 2017, 4:35 p.m. EDT 2 Replies
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have a 2D fluid flow model with a flow through porous media. There is one inlet with 20 mm/s inlet velocity and I assume conservation of mass.
I want to check that the numerical mass balance of the models close with a reasonable error. To estimate if the result is reliable and not create or destroy water numerically in the calculation process.
Considering what the blog says in www.comsol.com/blogs/how-to-calculate-mass-conservation-and-energy-balance/. I went to Results > Derived Values > Integration > Line Integration
The expression you use is written as: spf.rho*(vi).
Where spf.rho is the density of the fluid and vi is the velocity.
Can someone confirm that this is the correct way to calculate mass conservation in 2D models?
I want to check that the numerical mass balance of the models close with a reasonable error. To estimate if the result is reliable and not create or destroy water numerically in the calculation process.
Considering what the blog says in www.comsol.com/blogs/how-to-calculate-mass-conservation-and-energy-balance/. I went to Results > Derived Values > Integration > Line Integration
The expression you use is written as: spf.rho*(vi).
Where spf.rho is the density of the fluid and vi is the velocity.
Can someone confirm that this is the correct way to calculate mass conservation in 2D models?
2 Replies Last Post May 15, 2017, 5:03 p.m. EDT
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Posted:
8 years ago
Hi
Seems correct of vi is the flux velocity NORMAL to the outlet.
Lasse
Seems correct of vi is the flux velocity NORMAL to the outlet.
Lasse
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Posted:
8 years ago
Hi Lasse,
I'm not a comsol user and I'm following the steps to calculate mass Conservation and Energy Balance, (www.comsol.com/blogs/how-to-calculate-mass-conservation-and-energy-balance/?rnd=0.9605255224029794). I did not understand how they got the mass balance results for the transient analysis, You could share the expression of mass balance used
Best,
Katherine
I'm not a comsol user and I'm following the steps to calculate mass Conservation and Energy Balance, (www.comsol.com/blogs/how-to-calculate-mass-conservation-and-energy-balance/?rnd=0.9605255224029794). I did not understand how they got the mass balance results for the transient analysis, You could share the expression of mass balance used
Best,
Katherine