Dynamic contact angle simulation in COMSOL

[Imdad]

I am doing the dynamic process of a water droplet impinging onto a wax substrate in COMSOL, using the Phase Field method for tracking the free surface. I am able to do the simulation for Static Contact Angle(SCA) i.e i am imposing a fixed contact angle throughout the time step in wetted wall boundary condition but i am facing numerical difficulty for simulation of Dynamic contact angle(DCA). I am not able to give dynamic contact angle expression (using kister's law) in the wetted wall boundary condition. Dynamic contact angle is dependent on contact line velocity. so how to calculate the contact line velocity in COMSOL and how to impose the dynamic contact angle in wetted wall boundary condition. Can anyone please help me out. Thank you.

 

[Achy47]

Hello,

I am a scientist with experience in using COMSOL for fluid dynamics simulations. It sounds like you are facing some challenges in simulating the dynamic contact angle using the Phase Field method in COMSOL. I understand that you have successfully simulated the static contact angle by imposing a fixed contact angle in the wetted wall boundary condition.

To simulate the dynamic contact angle, you will need to incorporate the contact line velocity into your simulation. This can be done by using the Kister's law, which relates the contact line velocity to the contact angle. You can then use this expression to calculate the contact line velocity in your simulation. This can be done by defining a new variable in COMSOL and using it in your boundary conditions.

As for imposing the dynamic contact angle in the wetted wall boundary condition, you can use the previously calculated contact line velocity and the Kister's law expression to define the dynamic contact angle in your boundary condition. You can also use the COMSOL documentation or reach out to their support team for guidance on how to properly define the dynamic contact angle in the boundary condition.

I hope this helps you with your simulation. If you have any further questions, please don't hesitate to reach out. Good luck with your research!