嗨,大家好,
我是Moses的新用户,最近尝试用Moses模拟一艘长约2米的散货船模型,求出船舶在90度波浪条件下的RAO图。但是,我发现在设置波形频率范围时,最大频率只能设置在 2.09 rad/s 左右。 根据AQWA的经验,网格大小会影响最大频率允许范围,我尝试手动减小模型的网格大小,但没有奏效。如何将频率范围更改为大于 8 rad/s? following attachment is Moses Motion error when i am trying to enter a large frequency.
Hi, I had to use Google translate to read your question. Maybe some of the information translated is confused.
You are trying to analyze a vessel that is 2 meters in length? MOSES was not designed to analyze vessels of such small dimension. Have you considered using Maxsurf? Maxsurf is also a Bentley product.
I hope this helps.
Sorry, something wrong with my google chrome, yes, i am trying to analyze a 2 meters vessel with different water depths, I considered using maxsurf motion before. however, the maxsurf motion looks can not change the water depth.
You are correct you have to be careful of how to scale everything up and then how to scale everything back down. I would have to review my textbooks on model tests. Please review your textbooks for the proper way to scale.
Hi, I tried to scale my model up tp 10 times. However, It did not work, when I enter the frequency range, it still shows that I cannot enter the max. frequency more than 2.09rad/s
Hi, the size of the model is not going to take out the warning message. The reason for suggesting a larger model is so that you do not need to use 2.09 rad/s. A larger model will not need waves with such a large frequency.
In your first post you mentioned grid size. I am interpreting grid size to be the length of wave needed to calculate motions. A 2 meter model will need waves much shorter in comparison to a 20 meter model. I am saying change your grid size to fit the model.
Hi, just double-check, is creating and sizing grids in Moses Modeler-Trimmesh?
Thank you.
Yes, let us talk about the "grid".
When you mentioned the 2.09 rad/s this defines the length of a wave. It is common to need a wave at least the length of the body. That is why I suggested using a larger body. MOSES was not designed to create waves 2 m long. I think of this as the size of the grid used for the water surface.
There is a second grid. That is the the panels used to define the body. It is common to use a panel at least 1/5 the length of the shortest wave. If your body is 2 m long and you will be using a 2 m long wave, then the panel size needs to be at least 2/5 m on each side. I think of this as the grid for the body. Again, MOSES was not designed to make a wave 2 m long, that is why I suggested making a large body.
Now to your question. Yes, setting the panel size is done in MOSES Modeler. Yes, it is done with a trimesh.
Answer Verified By: YUN Yin