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June 8, 2021, 13:46 |
Floating Body Simulations
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#1 |
New Member
Will
Join Date: May 2021
Posts: 11
Rep Power: 5 |
Hello, I am still fairly new to the world of numerical modeling, and I am wanting to employ REEF3D to simulate the hydrodynamics of a simple, floating cylinder breakwater. Is there any available tutorial for a floating body simulation, as to this point, I have not found anything and am struggling to make progress. All simulations up to now have experienced the same problems of exceeding the critical velocities and the cylindrical body beginning to free-fall well outside of the domain.
Any advice and direction is greatly appreciated! |
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June 9, 2021, 06:25 |
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#2 | ||
New Member
Ali Burhan
Join Date: Apr 2017
Location: İstanbul
Posts: 13
Rep Power: 9 |
Hello Will,
I am also trying to analyze floating body using reef3d. The following options worked for me. For control.txt file: Quote:
Quote:
You can also change mesh and domain size. I hope that helps. Best regards. |
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June 9, 2021, 10:15 |
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#3 |
Senior Member
Arun Kamath
Join Date: Nov 2014
Location: Trondheim, Norway
Posts: 265
Rep Power: 14 |
In addition remember to activate/ deactivate the degrees of freedom that you want/ don't want in X 11
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Arun X years with REEF3D |
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June 9, 2021, 12:28 |
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#4 |
New Member
Will
Join Date: May 2021
Posts: 11
Rep Power: 5 |
Thank you for the guidance thus far. I will explore what I am able to with the input.
For clarity's sake in future replies, I have been able to run what appears to be a successful simulation with a rectangular floating body in the numerical wave tank, however, when switching to a cylindrical floating body the simulation fails. The only presumptive reason I have been able to identify, to this point, is a failure of the program to calculate the volume of the cylinder correctly, as it is often negative and on the order of 10^10+, when the prescribed dimension of the cylinder are obviously much smaller and much more realistic (i.e. r = 8.9 cm, L = 69 cm). If the error's persist, I will post my input files for review by someone more familiar with the software, but again, thank you for the information provided so far! |
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June 9, 2021, 14:31 |
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#5 | |
New Member
Will
Join Date: May 2021
Posts: 11
Rep Power: 5 |
Quote:
Regards and appreciations! |
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June 10, 2021, 04:13 |
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#6 |
Senior Member
Arun Kamath
Join Date: Nov 2014
Location: Trondheim, Norway
Posts: 265
Rep Power: 14 |
Hi Will,
Your input seems to be fine with respect to the floating body. I see that you run this for current and not waves. With that, I would say look at the following aspects: W 10 is the discharge and not the velocity. Too high a value here can cause "exceeding critical velocity" problem. I would also recommend using B 76/ patch boundary conditions to better define and control and inflow and outflow. Lastly, while CFL =0.3 works just fine, if the velocity errors persist, you might want to reduce the value. Addressing another query in the thread above: The floating objects currently do not have a collision detection algorithm. Therefore, if the object is too heavy and sinks (or sinks for other reasons) it will sink out of the domain as it does not detect the floor of the tank either. Of course by this stage the simulation is deemed to have crashed. That said, I am not sure why your cylinder sinks
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Arun X years with REEF3D |
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June 10, 2021, 16:01 |
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#7 |
New Member
Will
Join Date: May 2021
Posts: 11
Rep Power: 5 |
Hello Kamath,
Yes, the input files for the simulation above are for current, as I am attempting to run Ali's simulation to better understand. Now that I have started to better understand the parameters pertaining to the floating body, I'll soon be transition to my own simulations, which I hopefully will be able to perform now thank to all of your guidance. If problems continue to present themselves, I will submit a new set of input files that will reflect my own wave simulations along with my questions. Thank you all so far! |
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Tags |
breakwater simulation, floating body, hydrodynamics, reef3d |
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