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Adding a Faxen Force on Stokes drag force in Particle Tracing Module
Posted Feb 11, 2013, 8:13 p.m. EST Fluid & Heat, Microfluidics Version 4.3, Version 4.3b 1 Reply
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Hi everyone,
I am trying to use the particle tracing module with a non-uniform laminar flow in a channel. I am using "Drag Force" to trace the particles' motion. However, the Stokes force is defined without the Faxen Force in Comsol.
(oi46.tinypic.com/28c33nl.jpg)
I am wondering how I can add the Faxen Force on the equation. Is there already built-in physics module for Faxen Force?
Thanks a lot,
Damla
I am trying to use the particle tracing module with a non-uniform laminar flow in a channel. I am using "Drag Force" to trace the particles' motion. However, the Stokes force is defined without the Faxen Force in Comsol.
(oi46.tinypic.com/28c33nl.jpg)
I am wondering how I can add the Faxen Force on the equation. Is there already built-in physics module for Faxen Force?
Thanks a lot,
Damla
1 Reply Last Post Feb 12, 2013, 4:29 p.m. EST
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Posted:
1 decade ago
Dear Damla,
This force can be added to the Particle tracing physics by right clicking it and selecting "Force". The force components can then be added as:
Fx=pi*spf.mu*fpt.dp^3/8*(uxx+uyy)
Fy=pi*spf.mu*fpt.dp^3/8*(vxx+vyy)
An example is included in the attached model. Please note that the velocity field needs to be discretized using second order elements in order to evaluate this force (as done in the attached model). By default, COMSOL uses first order elements.
Using the defaults first order elements could also be done but it would require additional modifications.
Best Regards,
Fabrice Schlegel, PhD
COMSOL Technical Support Team
This force can be added to the Particle tracing physics by right clicking it and selecting "Force". The force components can then be added as:
Fx=pi*spf.mu*fpt.dp^3/8*(uxx+uyy)
Fy=pi*spf.mu*fpt.dp^3/8*(vxx+vyy)
An example is included in the attached model. Please note that the velocity field needs to be discretized using second order elements in order to evaluate this force (as done in the attached model). By default, COMSOL uses first order elements.
Using the defaults first order elements could also be done but it would require additional modifications.
Best Regards,
Fabrice Schlegel, PhD
COMSOL Technical Support Team
Attachments: