Waterfall to blade

How to create waterfall of 0.8cm radius? The water should fall onto the blade surface and rotate the blade. I tried using external flow but if the flow is small, I have to choose seed face. After choosing seed face, I cannot delete the solid part in the cylinder that I created for rotating zone.

Hello @zasyraf , thanks for using the Forum!

The task you mentioned would involve simulating the interaction between water and air, such as a waterfall. This requires using a type of simulation called multiphase simulation. There are two multiphase modules available in SimScale platform, and while both are accurate, the one in the Subsonic solver is more efficient in terms of computational resources. (both are available to professional subscriptions)

You would also need a 6 degree-of-freedom (6-DOF) solver, which would allow for analyzing the movement and rotation of objects in six different directions when they are subjected to fluid-driven effects. Neither of the multiphase solvers has a 6-DOF solver yet. However, there are plans to potentially add this capability to the Subsonic multiphase module in the future. You can refer to the SimScale product roadmap for more information on upcoming features and improvements. here.

I hope these would be helpful,

Thank you kaany. I already have the rpm of the blade when subjected to waterfall. Do I still need a 6-DOF solver? I am trying to get the water velocity before and after the impact to blades.

@zasyraf If you already have the RPM, then no you don’t need a 6-DOF solver indeed. A multiphase solver with rotating zone capabilities, which is available in both multiphase solvers in SimScale, should be sufficient.

Also to revisit your original question, SimScale CAD mode is only intended for modification purposes, we can prepare the model for the simulation phase. A better option would be to prepare your model in your own CAD software, and leave the clean up operations to CAD mode if necessary. You can alternatively pick one of the geometries presented in public projects to use for your own application.

May I ask if this project is for academic or commercial purposes?

Looking forward to hear from you,

Thanks for the reply kaany.

Which two are the multiphase solvers? Multiphase and subsonic?

I already have the model for rotating part. What I am having problem is to simulate waterfall to the rotating part.

This project is for academic purpose and I am using my academic enterprise plan.

Looking forward for your guidance.


To create a waterfall with a 0.8cm radius, try adjusting the flow rate and experimenting with different seed faces.

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Hello again @zasyraf !

That’s great! As an academic user, you should already have access to OpenFOAM multiphase solver which should serve your purpose well. As a starter I’d recommend you to have a look at some settings regarding the rotating zones in this documentation page, as well as on how to tune time step and CFL number in OpeanFOAM multiphase solvers in this documentation page.

I hope these are helpful,

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