Learning Forum

[issacdktn]

Hello, I’m having an issue with my analyses using AQWA. I perform the hydrodynamic analysis for regular waves and irregular waves. But, when I’m in the case of irregular waves, my platform sinks. however, in the case of regular waves, the platform does not sink; it floats. Moreover, the wave amplitude for the irregular waves case is very inferior (0.00001 m) than the regular waves case (0.45 m).

Please, can I have help which this issue?

[Shuangxing Du]

Please check the normal directions of the surfaces in your model. Aqwa requires that the normal directions of the surfaces should point towards the outerside fluid region.

[issacdktn]

Hello, Thank you for the answers.

Yes, I checked it in SpaceClaim. All the normal directions of the surfaces are pointing towards the outside.

[Shuangxing Du]

Please (1) check the Hydrostatic Results in Hydrodynamic Diffraction

 

(2) if it is possible, show a screenshot of your Aqwa Workbench model.

[issacdktn]

Hello,

Here is the screenshot of the hydrostatic analysis. The entire structure is made of three components : two identical components (Partie 1 and Partie 2) connected to a central component (Partie Centrale) by rod-ball joints. The central component is in water, while the other two are not.

[Shuangxing Du]

Thanks for sharing these information. It seems that Partie 1 is a fully submerged structure but without the structure mass. In the time domain analysis, this setting may cause the singularity problem when sovling the motion equation.  Please define the mass and moments of inertia of Partie 1 properly. If it is a fixed structure, you can make these values in the same orders of those of Partie Centrale.