Hull Simulation Gone Bad

yannis_v · September 22, 2020, 03:03

Hello everyone.

It is my first steps to OpenFoam and CFD in general, after completing a cfd class doing my master's degree. I tried to simulate the flow around a hull and estimate the drag coefficient, using the DTS hull example and a wiggley hull example I located, however both without enough documentation. The boundary conditions are almost an exact copy of the examples, and I made sure that the alpha factor was correctly calculated in zero time.

The mesh created using SALOME.

The code succesfully compiled (interfoam, k-omega), but when postprossecing, i realized that the water was leaving the domain

. I tried to attach some photos but unfortunately I was not able, so i included them in a google drive folder (https://drive.google.com/drive/folde...TF?usp=sharing). I also include the 0, constant and system folders.

I suspect that the problem lies at inlet / outlet configuration.

Please help a guy not give up just yet

Thank you all and keep up the good work!

ptpacheco · September 22, 2020, 10:05

Yannis, the link is not available...

yannis_v · September 23, 2020, 04:48

I'm so sorry.

Please find below the active link.

https://drive.google.com/drive/folde...TF?usp=sharing

Thank you for your assistance once again!

ptpacheco · September 23, 2020, 09:50

Yannis, it seems you have switched the inlet and outlet. This is what is causing your problem: you are setting the velocity in the inlet and intermal mesh to be (8.24 0 0) m/s but since the inlet is the furthest part of the domain along the x axis, the velocity is actually pointing out of the domain.

You can either switch back the inlet and outlet or just put a minus sign on your Umean.

Hope this helps!

yannis_v · September 24, 2020, 06:58

ptpacheco thank you for your time!

I will check and revert as soon as possible!

I hope you have a great day!

September 22, 2020, 03:03	Hull Simulation Gone Bad	#1
yannis_v New Member Join Date: Sep 2020 Posts: 4 Rep Power: 6	Hello everyone. It is my first steps to OpenFoam and CFD in general, after completing a cfd class doing my master's degree. I tried to simulate the flow around a hull and estimate the drag coefficient, using the DTS hull example and a wiggley hull example I located, however both without enough documentation. The boundary conditions are almost an exact copy of the examples, and I made sure that the alpha factor was correctly calculated in zero time. The mesh created using SALOME. The code succesfully compiled (interfoam, k-omega), but when postprossecing, i realized that the water was leaving the domain . I tried to attach some photos but unfortunately I was not able, so i included them in a google drive folder (https://drive.google.com/drive/folde...TF?usp=sharing). I also include the 0, constant and system folders. I suspect that the problem lies at inlet / outlet configuration. Please help a guy not give up just yet Thank you all and keep up the good work!

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September 22, 2020, 10:05		#2
ptpacheco New Member Pedro Pacheco Join Date: Dec 2019 Location: Portugal Posts: 10 Rep Power: 7	Yannis, the link is not available...

September 23, 2020, 04:48		#3
yannis_v New Member Join Date: Sep 2020 Posts: 4 Rep Power: 6	I'm so sorry. Please find below the active link. https://drive.google.com/drive/folde...TF?usp=sharing Thank you for your assistance once again!

September 23, 2020, 09:50		#4
ptpacheco New Member Pedro Pacheco Join Date: Dec 2019 Location: Portugal Posts: 10 Rep Power: 7	Yannis, it seems you have switched the inlet and outlet. This is what is causing your problem: you are setting the velocity in the inlet and intermal mesh to be (8.24 0 0) m/s but since the inlet is the furthest part of the domain along the x axis, the velocity is actually pointing out of the domain. You can either switch back the inlet and outlet or just put a minus sign on your Umean. Hope this helps!

September 24, 2020, 06:58		#5
yannis_v New Member Join Date: Sep 2020 Posts: 4 Rep Power: 6	ptpacheco thank you for your time! I will check and revert as soon as possible! I hope you have a great day!