Volume integration

Nimesh Bhanushali
Hello guys,

I have modeled drug release from a spherical pill in a 2D asymmetry mode and obtained the concentration profile. Need to obtain the volume integration over the entire pill. The equation for the same is attached below where rho is concentration at time t, phi is azimuthal angle of the pill, theta is the zenith angle, r is the radial position at which the concentration in to be calculated and its range is (0,1). I tried reviewing various models in application libraries, but could not find anything related to my model. please help me.

Thanks in Advance.
Nimesh

2 Replies Last Post Apr 24, 2017, 6:37 PM EDT
Gunnar Andersson COMSOL Employee
Posted: 6 months ago Apr 24, 2017, 6:50 AM EDT
If your integrand only depends on r and z, then you can use a Derived Values > Integration > Surface Integration feature: Make sure that you check the "Compute volume integral" check box. This check box modifies the volume element in the integral to take the axial symmetry into account.
If your integrand only depends on r and z, then you can use a Derived Values > Integration > Surface Integration feature: Make sure that you check the "Compute volume integral" check box. This check box modifies the volume element in the integral to take the axial symmetry into account.

Nimesh Bhanushali
Posted: 6 months ago Apr 24, 2017, 6:37 PM EDT
Thanks, Gunnar
My model is sorted. Just one more thing, I also need to calculate the leftover amount of drug released from the pill within the time range(0,10sec) and need to plot the graph of the amount of released drug versus the time. I have attached a screenshot at the end, where [(rho0*4pi/3) is the amount of drug at time t=0] and expression under the integral is the amount of drug integrated over the entire pill. Need help with this and my final model is ready. Please assist me.

Thanks in Advance.
Best Regards
Nimesh.
Thanks, Gunnar My model is sorted. Just one more thing, I also need to calculate the leftover amount of drug released from the pill within the time range(0,10sec) and need to plot the graph of the amount of released drug versus the time. I have attached a screenshot at the end, where [(rho0*4pi/3) is the amount of drug at time t=0] and expression under the integral is the amount of drug integrated over the entire pill. Need help with this and my final model is ready. Please assist me. Thanks in Advance. Best Regards Nimesh.

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