Star-CCM+ Hands on Tutorial | Multiphase Volume of Fluid (VOF) Dam Break Simulation
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- Опубликовано: 13 окт 2021
- This video is about Star-CCM+ hands on tutorial for dam break simulation using multiphase volume of fluid (VOF) approach. It will guide you how to model the geometry within Star-CCM+ and then follow on to do the 2D quadrilateral meshing using both laminar and turbulent flow modelling. Afterwards, the solver setup and boundary conditions used for unsteady incompressible flow involving gravitational effect. Finally the pos-processing to visualize and examine the results compared to the experiment.
#cfd #starccm #meshing
Further details of dam break model and test case can be found on following references:
1. Abdolmaleki, K., Thiagarajan, P., Morris-Thomas, M. Simulation of The Dam Break Problem and Impact Flows Using a Navier-Stokes Solver. 15th Australasian Fluid Mechanics Conference the University of Sydney, Sydney, Australia 13-17 December 2004.
2. Zhou, Z. Q., Kat, J. O. D. and Buchner, B., A nonlinear 3-D approach to simulate green water dynamics on deck, Nantes, 1999, 7th Intl. Conf. Num. Ship Hydrodynamics
Hello thanks for the video
I hope you're all doing well. I'm reaching out for some advice and guidance regarding a new project I'm tackling during my internship.
In the past, I've primarily worked with ANSYS, focusing on external flows, particularly on airfoils. However, my current internship project involves simulating sloshing behavior in oil tanks under various conditions.
The catch is that I've been asked to use Simcenter STAR-CCM+ for this task, which is new to me. I've done a bit of research and learned about the Volume of Fluid (VOF) method, but I was initially instructed to work with the Finite Volume Method (FVM).
I have a few questions and concerns about transitioning to STAR-CCM+ and understanding how to simulate sloshing effectively. Are there any tutorials or resources available for learning sloshing simulations in STAR-CCM+? Also, since I don't have access to a license yet, are there any alternative ways to familiarize myself with the software?
Thanks so much for this video. Only issue I had was that despite me giving a base size of 0.1m the displayed mesh had a much much lower resolution. Any idea why that would be?
You are welcome thanks for the feedback and nice comment ☺. Well there are several ways of doing meshing, you can choose large base mesh size and then refine your domain using geometric sources in the desired fluid region. Also one can even use mesh adaptive refinement with a coarse mesh. Hope this helps good luck.
@@Simulation-Engineer Sorry to ask another question but I couldn't see where the "volumetric local mesh refinement" parameter was used in the video. Is it a custom control or located in a different location? Thanks again
Yes its custom control.
@@Simulation-Engineer Sorry to bug you with another question but could you tell me the significance of " ?0.0:1.0 " and " ?1.0:0.0 " in the initial condition field functions? Is it defining the fraction of the phase within and outside the described area? So 0.0:1.0 means 0 inside, 1 outside? Thanks
@@pasty609 Hi Pasty, the purpose of using if condition is to define the intital volume fraction of water i.e if it is 0 mean its Air and 1 its Water -> Vice Versa. Thanks for the query and you are most welcome.
Thanks for the great video. I am looking to apply the multiphase model to a mixing scenario which means I will have a 3D - problem and two liquid phases. Do you know where I could find documentation on how to write field functions to define where liquid A and liquid B start? As I don’t know how to write them for a 3d problem; ideally liquid A would start in the bottom 1/3 and liquid B in third above. Thanks
You are welcome Tom, thanks for the feedback.
In your case I will do it using a field function let's say define the fluid levels by coordinates for example:
For liquid A:
Tools > Field Functions > New > User Field Function 1 > Properties
Type: Scalar
Function Name：Change User Field Function 1 to Initial_Height_Water
Definition: ($$Position[2] Field Functions > New > User Field Function 1 > Properties
Type: Scalar
Function Name: Change User Field Function 1 to Initial_Height_Oil
Definition: ($$Position[2]>=0.7)?1:0
$$Position[2]: Y direction (height)
@@Simulation-Engineer thanks for your response , I have input the filed functions as you have said but with position[3] as the z axis is my height. However when I initialise the simulation to see the volume fraction. The volume fraction of water is coming up as 1 and gas as 0. Do you know of a common error which may cause this?
The regions initial conditions have both been set to use the initial conditions from the continuum. And the continuum VOF is set to composite and has both the field function as inputs.
Well you need to check the field function logic it should work, thanks.
how can you get the zmax/min on extrude of model
Could you tell me the Star ccm version 2022 or 2021
Well its 2021 but tutorial is valid for almost all the versions, thanks.
Hello, I followed your tutorial but i can't seem to meet the same stopping criteria, do you have any advice on how to fix my simulation and is anyway possible you can send me your STARCCM+ files so I can try see for comparison?
Thank you!
How do you define where the water has to be and where the air has to be ? Was it using the field functions in tools? What should I change if I want to simulate a ship moving on free surface?
Well you should patch the water and air region using field functions and then initialize the flow to see the volume of fluid region if its properly patched or not. Normally in case of ship you patch the flow based on the draft line i.e. below this line is water and rest is air. Hope this helps thanks 😊