uncorrect interFoam forces results

Kil · January 28, 2020, 12:33

Hello everyone!
I'm new OpenFOAM user. I recently calculated the ship's resistance using the interFoam solver. To my great regret, it wasn't possible to get correct results.
The projection of pressure forces on the ship's hull in the X-direction has too large a spread (see the figure). Tell me please, what this may be caused by?
(I'm used OpenFoam Version 7 and DTCHull tutorial)

P.S. Sorry for my bad English

clapointe · January 28, 2020, 13:09

The tutorial uses the localEuler time scheme to compute a steady solution, so you will not see "correct" results until the simulation converges (i.e. you should only look at final result -- and even then it looks like you should run it out longer).

Caelan

Kil · January 29, 2020, 13:51

Quote:

Originally Posted by clapointe

The tutorial uses the localEuler time scheme to compute a steady solution, so you will not see "correct" results until the simulation converges (i.e. you should only look at final result -- and even then it looks like you should run it out longer).

Caelan

Could you help me to understand why, it was possible to calculate the pressure forces in the DTCHull tutorial with enough accuracy (see figure 1)?
Do I need to increase the number of iterations (i.e. reduce the time step) or do I need to improve the quality of the mesh (see figure 2)?

clapointe · January 29, 2020, 17:09

I have never run the tutorial; I am just trying to explain why you might be seeing the behavior you are seeing. Accuracy is always relative to the application, and I cannot comment on what is good enough for this case -- perhaps someone else with more experience could be of more help. Running it out longer or making the mesh better are both possible things to try.

Caelan

Kil · January 30, 2020, 13:23

Ok. Thanks a lot!

Kil · January 30, 2020, 13:27

Has anyone ever used DTCHull tutorial and intterFoam solver tell me please how I can get accurate results!

Kil · October 10, 2020, 14:14

As time goes on, there are more and more questions, but there are no answers to them....

January 28, 2020, 13:09		#2
clapointe Senior Member Join Date: Aug 2015 Posts: 494 Rep Power: 15	The tutorial uses the localEuler time scheme to compute a steady solution, so you will not see "correct" results until the simulation converges (i.e. you should only look at final result -- and even then it looks like you should run it out longer). Caelan Svetlana likes this.

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January 29, 2020, 17:09		#4
clapointe Senior Member Join Date: Aug 2015 Posts: 494 Rep Power: 15	I have never run the tutorial; I am just trying to explain why you might be seeing the behavior you are seeing. Accuracy is always relative to the application, and I cannot comment on what is good enough for this case -- perhaps someone else with more experience could be of more help. Running it out longer or making the mesh better are both possible things to try. Caelan

January 30, 2020, 13:23		#5
Kil New Member Serge Join Date: Nov 2019 Posts: 22 Rep Power: 7	Ok. Thanks a lot!

January 30, 2020, 13:27		#6
Kil New Member Serge Join Date: Nov 2019 Posts: 22 Rep Power: 7	Has anyone ever used DTCHull tutorial and intterFoam solver tell me please how I can get accurate results!

October 10, 2020, 14:14		#7
Kil New Member Serge Join Date: Nov 2019 Posts: 22 Rep Power: 7	As time goes on, there are more and more questions, but there are no answers to them....