CFD Online Discussion Forums

CFD Online Discussion Forums (
-   EnSight (
-   -   How to Calculate Mass Flow Through Boundary (

cfdvenkatesh June 22, 2015 16:12

How to Calculate Mass Flow Through Boundary
I have transient data loaded into EnSight. How to I calculate mass flow through inlet boundary and plot it in graph.
Also I would like to animate the graph by highlighting mass flow at current time.

Marina G June 23, 2015 14:40


Select your inlet boundary part in the part list. Open the calculator tool (icon at the top-left). If you have the density field, then calculate Momentum = velocity*density. Then, calculate the Mass flow by using the "Flow" function (that calculates the Surface integral of the input vector field) setting Momentum as the vector field. Give a look at this link for more details on the Flow calculations (in particular, point b) focuses on Mass flow calculations):

You should now have created a new variables that is your Mass flow. It will appear in the variable list (bottom-left) under Constants - in EnSight, "constants" means constant in space, not in time. Right-click on it and select "Plot vs. time". The plot of the flow vs. time will appear on the viewport. If you change timestep, the vertical line corresponding to the time at which you are will update automatically.

Would you have more questions or problems, let us know.
Best Regards,

Marina Galvagni
CEI Software Engineer Support

hiren tala March 15, 2018 09:16

I have to calculate massflow rate of Co2 out of mixture of 5 gases available in the pipe at the one cross sectional surface. how can i show and calculate perticular for one gas only? what you mensioned above is for Total massflowrate.
Any reply will be appreciable.
thanks in advance

Marina G March 15, 2018 09:47


I assume you have quantities such as: density of the gas (scalar field), species concentration for the gas component you're interested in (scalar field), gas velocity (vector field). And, you have a 2D part which is the cross section where you want to calculate the mass flow.

In this case, first create a new variable:

species_momentum = species concentration * density * velocity

This will be a vector field that is the momentum for only that species, not the whole gas.
Now calculate the Flow and FlowRate using this species_momentum instead of the velocity.

Give a look at

for more details on the flow calculations in EnSight.
Best Regards,

Marina Galvagni
CEI Software Support Engineer

hiren tala March 16, 2018 05:49

thank you so much
i got it

All times are GMT -4. The time now is 13:00.