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solving ship resistance divergence

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Old   April 25, 2021, 05:13
Question solving ship resistance divergence
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Jiayu Sun
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Dear Foamers and Ship designers:

I am doing the ship resistance simulation refering to DTCHull setting. I think the only changes I made are the mesh and initial value of turbulence variables.
The mesh is encrypted near the hull,as shown in the figure below.The initial value of turbulence variables are caculated by the formula in this paper
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https://scholar.google.com/scholar?q=Uncertainty+analysis+in+ship+resistance+prediction+using+OpenFOAM&hl=zh-CN&as_sdt=0&as_vis=1&oi=scholart
. The velocity is 1.057m/s.So the initial k value is 0.00067.The initial omega value is 59.07.The initial nut value is 0.00002.I attach a screenshot of the formula in the paper below.The mesh check is ok.By the way,I did not take the hull motion in to accout. But the resistance shows strong oscillation as showing below.

Any suggestions?
Thank you in advance.
Jiayu Sun
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File Type: jpg mesh_setting2.jpg (136.0 KB, 22 views)
File Type: png 1619341674(1).png (9.0 KB, 29 views)
File Type: jpg 1e746636d8aed9b43b83169178d9625.jpg (45.7 KB, 25 views)
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Old   April 26, 2021, 03:43
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Jiayu Sun
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FYI:
Problems caused by incomplete boundary coverage when setting phase fraction field.

The oscillation caused by the physical model is more obvious than that caused by the numerical scheme.
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