Reply To: two interraction body in AQWA

[Shuangxing Du]

1-Are they should be floating fender or fixed?Can I define the distance between piston and cylinder like 2 mm. Is this gap to small?

They should be fixed fenders. It will be good to define the fixed point (on the external cylinder) away from the internal surface of that cylinder, in order to make the size of the fender to be larger than 2mm to avoid the error shown in the error message of "ZERO/NEAR ZERO SIZE ...".   Normally the size (not less than the initial distance between the fixed point to the contacting surface) should be greater than 0.001*G, where G is the acceleration due to gravity.

2-To get result from Hydrodynamic Diffraction I had the delete one of the inner surface. If I dont delete the surface , I had to divide into two component and use to joint. But with joint, I guess I had another problem during the Hydrodynamic responce so this time I just delete it.

The inner surface may not be neccessary to be deleted, instead you can define the surface as non-diffracting and set this surface and the bottom surface in a single part.

3- Should I define Interracting structure groups to get result in Hydrodynamic responce.

As the relative motion between piston and the external cylinder is large, it may be good if you can avoid them to be in the same hydrodynamic interaction group.

4-Diactivated freedom for both structure on X,Y,RX,RY. Regular wave is defined. What is missing?

As the fenders are defined in two horizontal levels, there is no need to deactivate freedoms of X,Y, Rx, Ry.  But do you need to find mooring lines (or connectin joint to the fixed point) to keep the external cylinder to the desired position?