[jbo]

Hello everyone,

I have a little experience with FineMarine in the context of ship resistance. Currently, I am experimenting with OpenFoam 11. I have downloaded the DTC Hull tutorial from OpenFoam 10 and have run it without making any changes.

I am comparing the results with the following paper:

el Moctar, Ould & Shigunov, Vladimir & Zorn, Tobias. (2012). Duisburg Test Case: Post-Panamax Container Ship for Benchmarking. Ship Technology Research. 59. 50-64. 10.1179/str.2012.59.3.004.

Here are the results:

m/s simul. exp.
1.335 14.46 20.34
1.401 17.40 22.06
1.469 19.96 24.14
1.535 24.24 26.46
1.602 23.50 28.99
1.668 25.32 31.83

The size, velocity, temperature, and other parameters are the same. I assume this tutorial was created specifically for this purpose.
I am sure many of you have already done this exercise, but I can't find answers to the following questions:

1. Such a difference... Is it just a simulation issue, or is the setup different as well? (For example, are there differences in the appendages?)
2. Is there a better tutorial or setup to compare OpenFoam 11 with experimental measurements?

I look forward to hearing from you.

[wkernkamp]

I plotted your result against the experiment. Are you sure that your runs are fully converged? The test cases are sometimes limited in the number of iterations to limit the test times.

[jbo]

Originally Posted by wkernkamp

Are you sure that your runs are fully converged?

To be honest I don't know. I just assumed the tutorials were designed to showcase best practices.


This is the controlDict I ran :

https://raw.githubusercontent.com/Op...em/controlDict


Any tips to get closer simulation ?


By the way I am not even sure whether or not appendages where present in Moctar 2012 experiments. What did you conclude ?


Regards


Julien

[JNSN]

Hi Julien,


from the controlDict you shared it seems you are running "DTCHull", which means time scheme LTS (pseude transient) and fixed hull (no trim and sinkage).

From my experience it is hard to get a converged solution with LTS, at least with the tutorial settings.
I suggest have a look at the "DTCHullMoving". This should be a good starting point.
Regarding the experimental setup: The resistance tests had been done with rudder.
In case you want to include the rudder, the geometry can be found on the website of University of Duisburg-Essen: https://www.uni-due.de/ismt/ismt_dui...est_case.shtml


Best,
Jan